lit : » CHEMISTRY APPLIED TO ARTS MANUFACTURES. BY M. J. A. CIIAPTAL, MEMBER AND TREASURER OF THE FRENCH SENATE ; GRAND OFFICER Ol'' THE LEGION OF HONOUP. ; MEMBER OF THE NATIONAL INSTITUTE ; HONORARY PROFESSOR OF THE SCHOOL OF MEDICINE, &C. &;C. oCC. IN FOUR VOLUMES. VOL. I. ■ N ; PRINTED FOR lliCIIARD FHILLIPS, No. 6, Bridge-street, Blackiriars. ISO7. By T.Gillet, Wild-Court, TF PREFACE, A TREATISE on Chemistry ap- plied to the Arts, cannot be a treatise on each art in particular. An under- taking of that nature would not only ex- jceed the ability of any individual, but such a work must necessarily abouncl ^ith tedious repetitions. The air, wa^ ter, heat, li;^ht, act according to the same laws in the hands of every class of artists ; and it is sufficient to point out the respective properties of all these agents, and the law of their action, tq a2 IV PREFACE. give every artist a competent idea of the cause, motive, and principle of his opera- tions. The best wa}^ of illustrating the arts consists not so much in describing their processes with accuracy, as in reducing all their operations to general principles. The description of an art, however cor- rect it may be supposed, is nothing more than the historj^ the picture of the ex- isting practice. It may, indeed, raise all artists to the same level in point of knowledge, b}^ the communication of the same processes, but it does not en- able ingenuity to advance a single step ; while science reflects a light on every operation, elucidates all their results, makes the artist perfect master of his PREFACE. V processes, varies, simplifies, and im- proves them, foresees and calculates all their effects. A treatise on Chemistry applied to the Arts, is therefore an elementary work ; and I shall think that I have attained the object I had in view, if every artist finds in this performance the cause of all his results, and the fundamental rule of his conduct. A work of this nature could not have been composed till the facts were suffi- ciently numerous to be compared with each other, and till analysis was brought to such a degree of perfection as to ex- hibit, in the products of an operation, the cause and the results of all pheno- VI PREFACE. nomena. Time, therefore, was requi- site to prepare the materials. Facts existed anterior to the science that was to iUustrate, to collect, and to compare them. Science is like the me- thods of naturalists, vv^hich could not be established till the knowledge of a vast number of animals allowed them to ex- amine and compare their principal cha- racters. But, in order that chemistry might elucidate the arts, it was necessary that itself should have acquired a profound knowledge of all the agents, of their pro- perties, and of their action ; it was re^ quisite that all bodies should have been classified, that all their effects should have PREFACE. Vll been calculated, and reduced to general principles. The conclusion of the eighteenth century accomplished this re- volution. Elements before unknown were added to those with which the che- mist was previously acquainted ; the ana- lysis of air and water came forward to il- lustrate the action of those two sub- stances ; the decomposition of acids af- forded an explanation of their principal effects ; the fluids of heat and light, those fertile sources of action and of re-ac- tion, those primary principles of vitality, took their places among the elements of bodies. Chemistry, which had hitherto been confined to particular operations, became, all at once, a central science from which all tj^ings emanate, and to which all things return. Man soon discovered that uature, equally simple ia via PKEFACE. lier principles of action, and fertile in the means of unfolding' them, is govern- ed by a small number of general laws ; and artists heretofore separated from each other in the vast field of genius, for the first time, perceived that they were united by the closest relations, and that their operations were regulated by prin- ciples common to them all. Chemistry applied to the arts will, therefore, be that science which, from the comparative analysis of the opera- tions of all the arts, will deduce certain ojeneral laws, to which the innumerable effects observable ttf'the practice of those arts may be referred. Considered in this, point of view, tlie chemistry of tliie arts may be pronounced PREFACE. XI a pharos, which the hands of man has erected in the sanctuary of the operations of art and nature, in order to throw a n<>ht over all its details. But the chemistry of the arts is not conlined to the elucidation of what is already known, or to the improvement of what is already practised. It daily creates new arts ; and within the period of a few years we have seen it teaching new methods for the bleaching of cloths, manufacturing ammoniacal salt, alum, and copperas ; decomposing marine salt for the purpose of extracting soda ; en- riching the art of dyeing with new mor- dants ; forming saltpetre, and refining it by the simplest processes ; composing powder by methods the most certain and k ?REFAt:E. expeditious; reducing the tanning of hides to its genuine principles, and abridging its operations ; improving the extraction and working of metals ; sim- plifying the distillation of wines ; econo- mizing the means of producing heat; establishing the combustion of oil, and lighting our habitations on new princi- ples ; and furnishing us with expedients to soar aloft in the air, and to consult nature three or four thousand fathoms above the surface of the earth, ^ Before chemistry had reduced the nu- merous operations of industry to ge^ neral principles, the arts and manufac- tures w^ere, if I may so express myself, the appanage of certain nations, and the property of a few individuals ; the most PREFACE. XI impenetrable secrecy covered ev6ry pro- cess with the veil of mystery ; forms and practices were transmitted as an inherit- ance from one generation to another. Chemistry has revealed every thing : it has rendered the arts the patrimony of all ; and in a short time we have, seen the nations by Avhom this science has been cultivated enriching themselves with tlie establishments of their neighbours. The preparations of lead, copper, and mer- cury ; the works in iron ; the fabrication of acids ; the manufacture of stuffs ; tlie printing of colours upon cloths ; the composition of crystals, of baked earths, of porcelains, &c. all these have been drawn forth from the womb of mystery, and are now common property. Xii PREFACE. Thus, in the course of twenty years, chemistry has created various branches of industry ; it has improved a still greater number, and made public almost all the processes of the arts. But while we admit that chemistry has rendered important services, while we hope that it will perform still greater, when its researches, enlightened by the progress of science, shall be more parti- cularly devoted to the arts ; we cannot help forewarning the artist and the ma- nufacturer of the abuse which is made of the term chemistry, and intreatixig them not to place a blind confidence either in all tlie works which bear that name, or in all those who assume the title of che- mists. Chemistry has its adepts and its PREFACE. XUl empirics, as well as the other sciences: The manufacturer might easil}^ ruin his fortune and his reputation, were he to regulate his conduct, or ground his spe- culations on calculations made in the closet, on the petty results of the labo- ratory, or on specious, but delusive ad- vertisements. Innovations, however advantageous they appear, should not be introduced into manufactures but v/ith the sfreatest circumspection. Before we change what exists, before, we alter what already pros- pers, before we derange a course of ope- rations under the idea of improving them, experience ought to have decided the superior advantages of tlie projected clianges, and the new proce.ss siiould XIV PREFACE. have received the sanction of practice, and even the approbation of the con- sumer. Without these salutary, prudent, and necessary precautions, which the theorist is pleased to term obstinacy, prejudice, and ignorance, the fairest establishment is soon disorganized. The manufacturer wavers for some time in doubt, darkness, and uncertainty ; and, after ruinous ex- periments, he is glad to return to his ori- ginal method, and to re-establish his re- putation on its former basis. But though I commend the cautious prudence of the manufacturer, who, al- most inaccessible to new ideas, adopts no change till it has undergone the test of PREFACE. XV practice and of his own experience ; I blame the obstinacy of hnn who rejects, without examination, all the improve- ments that are proposed to him : for he Avho does not endeavour to keep pace with the arts will soon be left behind. He finds that his productions gradually become disliked ; he can no lono-er af- ford them at so low a price as his com- petitors ; and instead of imitating them, he censures their new processes, which he treats as dangerous innovations ; he petitions government for regulations that the fabrications may be ren- dered uniform, he demands that it may be shackled with inspectors, and loud- ly invokes every thing that can retard the enlightened progress of the^arts. XVI PREFACE. In consequence of this fatal blindness, we have beheld the decay and ruin of establishments which had flourished for ages ; and, from the same cause, we daily behold the arts emigrating from city to city, or from nation to nation. The manufacturer is therefore placed between two rocks ; that of blind cre- dulity, which risks his fortune in ha- zardous speculations ; and that of ob- stinate mistrust, whicli undermines the foundation of his establishment by pre- venting the introduction of methods that are capable of improving it. True wisdom, therefore, consists in bestovvinsi; due attention on all discove- .ries ; in making trial of every thing that PREFACE. XVH iias the sanction of experience, or the testimony of professional men in its fa- vour ; but not to adopt as a method of fabrication any that has not undergone the test of a sufficient practice. I have ever considered it impossible for the chemist to unite in his labora- tory all the elements of calculation on Avhich the manufacturer ought to ope- rate, before he decides on any subject. The workmanship, the expences of esta- blishments, the interest of capital, the facilities of sale, the taste or the caprice of the consumer, the nature of the soil, the supply of fuel and primary mate- rials, are all data which are necessary to be known, weighed, and calculated; and the manufacturer alone is able to pro- VOL. I. b XVni PREFACE. cure suiricient iuformation, in order to obtain results on which to ground his decision. In this wliole affair, then, there are two distinct objects, that of the chemist, and that of the manufacturer ; the first proposes, the second judges and decides. What appears most advantageous to the chemist may not be so to the manufac- turer, because the chemist consults no- thing; but science, while the manufac^ turer is acquainted with existing circum- stances, compares tlie expence with the profit of the improvement, weighs the results of the two processes, consults the ta:te of the consumer, and grounds his decision on a multitude of facts and cir- c'.Uiistances which the cliemist can nei- xher knr.w nor appreciate. PREFACE, XIX Thus the chemist and the manufac- turer have it in their power to render mutual assistance to each other : but each must confine himself within those limits which the nature of their respec- tive studies has chalked out. Any in- version of this order of thinojs cannot fail to produce confusion, and lead to re- sults ruinous to their fortunes, and dis- creditable to science. But vain would be the attempt to im- prove the arts by means of chemistry, to raise them to that superiority on which depend the glory and the wealth of states, unless other causes co-ope- rated with science to insure their pros- perity. b2 XX PREFACE. Tlie most powerful cause of the suc- cess of a manufacture is, doubtless, to be found in the good quality of the articles, and the economy of their fabrication : but the most intelligent man will behold the germs of his industry languish un- der his hands, if other protecting causes do aot facilitate their expansion. Supposing a person to be in possession of all the knowledge and information re- quisite to form and to direct an estab- lishment, it is further necessary for its prosperity, that it be formed in a favour- able situation. A branch of industry cannot be fixed indiscriminately, or at random on this or that particular spot ; the place adapted to each has been mark- ed by the very nature of its operations ;^ PRtLFACt. XXI each has its peculiar soil, and not with- out the heaviest inconveniences can this natural order be inverted. The importance of local situation is particularly great for all the arts whose productions are low in price, and in which the workmanship is a very inferior consideration. Such should be estab- lished near the places from which the}- are supplied, and at no great distance from those where the products are con- sumed, because they can neither bear the -carriage of the primary material, nor that of the manufactured article. The power of locality is less absolute over objects of luxury. Thus a pottery /or coarse wares should be erected on the XXll PREFACE. stratum of clay of which they are made, and not far from the places where they are consumed, or of canals and rivers which facilitate their conveyance ; where- as a porcelain manufactory may flourish in the centre of a large city, because there the workmanship is every thing, and the primary materials scarcely enter as an element into the price of that pot- tery. All the arts in which the workmen, the materials, and the means are col- lected with diificuity, ought perhaps at first to be established in cities. There men, drawn together by necessity, exist b}' their industry alone ; they form, if I may be allowed the expression, a com- mon fund of all their resources, and di- PREFACE. XXUl vide all the operations anioiig them, in order the more speedily to accomplish their purpose. It would even appear that such of the arts as require great in- telligence and a perfect taste^ cannot flourish but in the niid&t of great cities, because there only can we hope to fun] the necessary resources. Not only are certain situations im- proper for the supply of the consump- tion and the workmanship of a manu- facture, but there are places, whicli, though possessing all these advantages, are inimical to certain kinds of manufac- tures, for reasons deduced from the very nature of the soil. Thus a spot which presents great resources for agriculture, and supplies all its inhabitants with rea- XXIV PREFACE. dy means of subsistence, cannot support any manufactures but such whose exist- ence is naturally connected with that of the productions of the earth. On these principles it is that manufactures of linen, wool, silk, hemp, and wine, instead of being prejudicial to agriculture, multi- ply its resources, provided they engage the husbandman only during that season of the year in which they require his at- tention. Establishments for mechanical arts, or objects of luxury, would cut up territorial prosperity by the very roots. We sometimes obsepve manufactures which seem to flourish for some time, though placed in situations that would appear unfavourable to them. This pros- perity is but a forced state ; the fortune PREFACE. XXV of the proprietors, the skill of the ijia- nagers, the favours of government, may prolong their existence to a few years; but as it is not in the power of man to remove the causes of ruin wliich are in- cessantly in action, their power over- whelms all his efforts ; ant:! after an ar- duous struggle, we behold the downfal of establishments, to whose prosperity nothing was wanting but the choice of a more suitable situation. Thus glass- houses, foundries, and other works which consume a great quantity of fuel, are ar- rested, at their very outset, by the hand of death, ^vhen they are estabhshed at a great distance from forests or coal mines. We have already observed, that the arts of luxury and manufactures of stuffs XXVI PREFACE. may thrive in cities, where a numerous assemblage of individuals affords them I'esources which ca.inot be expected in ether situations. But how are these ad- vantages counterbalanced by the incon- veniences which attend the crowding to- gether of so many workmen on so small a spot ! What an awful spectacle to be- hold twenty or thirty families, whose ex- istence essentially depends on the pros- ^perityofa manufactory ! A political re- volution, a change in the prevailing taste or fashion, a declaration of war, paralyse the activity of these manufactures ; and we see, almost in a moment, the indus- try and livelihood of forty thousand per- sons checked and cut off amidst the an« guish of penury and despair. PREFACE. KXVll I have always considered these alarm- ing assemblages as one of the greg-test calamities attendant on the progress of civilization, and I think it wise and pru- dent policy to prevent tliem. Not only do they every moment threaten the pub- lic tranquillity, but they endanger the fate of the art itself, since they expose it to the extremely variable chances of all those events vrhich act so powerfully on the population of cities. To combine the exquisite taste that exists only in cities with tiie facility and economy of ^\'orkmanship which are found in the country, without running the risk of the fatal consequences arising from the crowding together of workmen which we have already noticed, it is my xxviii pheface. opinion that the proprietor of an estab- lishment should reside in cities, while the hands engaged in the execution may be dispersed in the country. By these means the former enjoj^s daily opportu- nities of consulting the taste of the con- sumer ; he is surrounded by artists and men of science^ who enlighten him ; he possesses all the facilities that can be de- sired for obtaining supplies of the pri- mary material, and for the consumption of his productions ; he causes the arti- cles, made at a low price in the country, to be first prepared under his own in- spection ; he increases or contracts his business, according to circumstances, and upon the simple calculation of interest, because he is not afraid lost the luisband- nian, who gives to manufactures only so PREFACE. XXlX much time as he cannot employ in agri- culture, should fall into a state of lethar- gic indolence, in consequence of the ces- sation of his engagement in the former branch of industry. If we direct our attention to the manu- factories which have flourished for a lona; period of time, which have been unas- sailable by the storms of revolutions, the caprices of fashions, and the versatility of the laws and regulations imposed on commerce, we shall find them all situat- ed in the country, where the barrenness of the soil, and the inclemency of winter, prevent the inhabitant from following without interruption the employment of cultivating the earth ; and experience teaches us, that thou oh the means of XX5t PREFACE. execution are less perfect in the bosom of mountains, and beneath the roof of thatch tlian in cities, yet the produc-^ tions manufactured there are offered in all the markets of Europe, at a lower price than those of cities ; the reason of which is, that as workmanship is there lower, it balances with advantage against the more imperfect means of exe- cution. But the advantages of local situation, and the intelHgence of a manager, can- not insure the prosperity of an estab- lishment, niiless the protection, the en- couragements, the laws, and the regula- tions of a state are calculated upon the true interests of manufactures. PREFACE. XXXi All governments are, doubtless, will- ing to protect the arts and commerce ; but there are few whose conduct, in this particular, comes up to their good inten- tions. A government that is truly the protector of industry is ever attentive to the arts, and its expedients to facilitate their developement, and to insure their prosperity, are reduced to the following : To render the supplies of primary ma- terials easy, and to facilitate the con- sumption ; to grant premiums on expor- tation, that the productions of the na- tional manufactures may find their way into ail the marts of Europe ; to em- ploy its credit with other governments for the purpose of obtaining a knowledge- of improvements, and new processes v/herewith to enrich its own countrv ; to XXXll PREFACE. determine, and to maintain with energy, the relation which ought to exist be- tween the workman and the master ; to consult the soil, the climate, the cha- racter of the inhabitants, and the inte- rests of agriculture, that it may grant none but a judicious protection, &c. Consistently with these principles the French government ought to devote its particular attention to the manufactures of wool, silk, flax, hemp, the distillation of wines, the making of earthen-ware, and all those articles for which the pri- mary materials are abundantly supplied by the soil. It is only from a deplorable inversion in tins order of things that we have, for half a century, seen it encou- rage the cotton manufactures, without PREFACE. xXxiii reflecting that the fate of these estab- lishments, suppUed with materials from abroad, was liable to be affected by all the chances of revolutions, by all the intrigues of cabinets, by all the variations of laws re* lative to the customs, and thattlie manu- factures essentially territorial would suffer so much the more by this competition, as, in order to encourage, multiply, and consolidate these infant establishments, it was necessary to grant premiums, to prohibit the importation of analogous productions, and to direct all the capi- tal, the science, and all the hands in the country to this truly exotic branch of in- dustry.* * I am only speaking of wliat ought to have been done fifty years ago. Now that the cotton manu- VOL. I, C XXXIV PREFACE. It is likewise in consequence of view- ing objects in a wrong light that govern- ments strive to establish every brarlch of industry in their respective states, with- out reflecting, that every country, from its position, its climate, the nature of its soil, and the character of its inhabitants, has certain arts and manufactures which factures form a considerable branch of our industry, now that they employ nearly two hundred thousand persons, it is, doubtless, (he duly of government to protect them. But was it wise policy to establish them in France? Has not their introduction been detrimental to the essentially national manufactures of linens, woollens, silks, &c. WoiK(^ not the go- Ternment have acted more prudently, hah bestow- ed encouragements on the above-mentioned manu- factures, and left those of cotton to our rivals, as means of exchange against the productions of out industry and our soil ? There lies the question. PREFACE. XXXV belong to it, and form, as it were, its in- heritance ; without reflecting that a na- tion desirous of doing every thing, and having every thing, separates, and cuts itself oif from the rest of nations, that it reserves no medium of exchange, and that the true relations of commerce can- not be established, except upon the re- spective exchange, either of the produc- tions of the soil, or of the productions of industry. It is further a necessary consequence of that forced state, and of that false di- rection which is given to industry, that governments conceive themselves oblig- ed to prohibit the importation of the productions of foreign manufactures. Besides these considerations that such c2 XXXVl PREFACE. prohibitory laws would be unnecessary, were each nation to confine its indus- try to such objects alone as nature her- self seems to have pointed out ; and that it would then be sufficient to lay a duty on importation proportionate to the prime cost of the articles, on all similar productions of foreign manufacture ; these laws organize fraud, corrupt the morals of a portion of the people, and have a prejudicial influence on the pro- gress of the arts ; for the manufacturer does not strive to improve, unless he has before him articles of a better or more economical manufacture than his own. Take away these objects of comparison, and content with his work, because he finds means to dispose of it, he falls asleep in his state of mediocrity. PREFACE. XXXVll We daily hear people assert the ne- cessity of making regulations for manu- factures^ and re-establishing inspections, in order to render them flourishing. Such contend for the propriety of re- storing the system of regulations adopt- ed by the great Colbert. They of course do not see, or affect not to perceive, that we are in such times and situations as cannot be compared to the period in which that celebrated man appeared. The arts were then either unknown or in their infancy ; in this feeble state it was doubtless necessary to assist, to fix them, and to establish their credit ; and as soon as any method of fabrication was ascertained to be advantageous, it was prudent to make a law of its execution, in order to preserve and to extend its XXXVlll PREFACE. practice. Had it not been for this wise precaution, the first steps of the artist, yet unsteady, would have led him astray. But now that all operations are calcu- lated, familiarised by practice, and elu- cidated by the sciences, the manufac- tui'er has released himself from his lead- ing-strings, and his further advances re- quire his perfect independence. Regu- lations for manufactures, by confining the artist to one uniform course, leave no scope for his imagination. I'o the too rigid observation of them it is owing that we have been distanced in the career of manufacturing industry by a rival nation. France never exerted all her genius till those barriers were broken down : since that moment the manufac- ture of cloths has been improved, the PREFACE. XXxix fabrication of casimeers has become known, and the freedom given to manu- facturers has introduced a variety of stuifs, and an improvement in tlie pro- cesses, which have in a short time raised our fabrics to a level with the best in Europe. Regulations for manufactures may indeed secure the present, but they ruin the future, and form a code of rou- tine and of prejudices. I know tliat all the manufacturingf towns where industry languishes, loudly call for regulations for manufactures ; I even know that almost ail of them as- cribe the decline of their sale to the suppression of these regulations ; but I likewise know, that were they to look round than, they would see either that xl PREFACE. the manufacture has removed to other places, because its estabhshment found there certain advantages ; or that the consumer has formed other connections, because he can be served at a lower price ; or that the fabric has been im- proved in other manufactories, while theirs has remained the same : or that political movements, or treaties of com-^ merce, have altered their relations with the nations which consumed their pro- ductions ; or finally, that the capricious taste of the consumer has led him to prefer other articles. I have no doubt that, on examining all these causes, the honest manufacturer would find which of them it was that operated to his disad- vantage, and that instead of hoping to promote, by regulations, the progress of PREFACE. Xli cliscoveiy, and the efforts of imagination, he would strive by the application of new processes to raise his manufacture to the state of prosperity from which it had fallen. Some of them thought that they pleaded the cause of the consumer in de- fending that of regulations ; l)ut this is also an error which it is of consequence to refute. The consumer is the best judge of the merchandize which he pur- chases, and it is the interest of the ma- nufacturer to supply him with a good commodity. The relations between the two classes of men are not permanent, inasmuch as they are established on their respective interests. Regulations and inspectors may, indeed^ insure an inva- xlli PREFACE. nable fabrication, but this is not always wiiat suits the consumer ; for if he wants a shght and cheap stuifj.why should he be obliged to buy one that is strong and expensive, and that he has no intention of using ? In my opinion, the liberty of making stuffs of all qualities, and of all dimen- sions, is exclusively to the advantage of the arts and of commerce : for industry cannot unfold its resources, unless it has sufficient latitude to apply all its me- thods. The interest of industry con- sists less in the makins: of a rich and ex- pensive dress, which is kept for a long time, than in the fabrication of more sim- ple garments which consume a greater quantity of the primary materials, employ PREFACE, xliii more hands, and occasion a quicker cir- culation. Regulations are necessary only for objects of which the mere inspection will not enable you to form an opinion : such as works in gold and silver. It is the province of the government to fix the quality, and to render the composi- tion uniform. The government might likewise require each manufacturer to stamp his name on ail his goods, as a warrant}^ to the consumer ; but this is the utmost that it ought to do. What a benefit would a o'overn- ment confer on the arts, if, insttid of forming regulations, and appointing in- spectors to superintend their execution, it were to send into the manufactories the most skilful persons to improve the Xliv PREFACE. methods of fabrication, to introduce the ameliorations of which they are suscep- tible, and the processes and machinery which are adopted in foreign establish- ments I Our observations concerning regula- tions may be applied without exception to trading companies or corporations ; for these institutions, under the pre-^ text of furnishing society with ma- nagers of manufactories skilled in the principles of a judicious practice, reject- ed such persons whose rising talents ex- cited the jealousy of their examiners, to whom they were likely to become rivals. But what will appear most extraordi- nary is, that these institutions should have subsisted so long as they did, though they were daily accused and condemned PREFACE. xlv by experience. At Paris, for example, industry took refuge in the fauxbourg Saint Antoine and in the Temple, for no other reason than because companies and corporations were there unknown. After liaving shewn what the artist ia capable of performing, and what it is the duty of government to do for the prosperity of the ai"ts, it remains for me to make a few remarks on the influence which belongs to the consumer. As the artist works only for the consumer, he should naturally adapt his fabrication to the tastes, and even to the caprices of the latter. The consumer may therefore be considered as the actual regulator of the operations of the manu- facturer. Pie directs the workman in bis plans, and in their execution ; and if Xlvi PREFACE he has taste, he rejects all that is not perfect, and occasions the artist insensi- bly to become familiarised with the beautiful ; but if he is deficient in taste and intelligence, he causes him to de- viate from the proper track. If the consumer were to order and to purchase none but perfect commodities, the workman would soon turn no other out of his hands. If, on the contrary, the consumer cannot distinguish a faulty from a faultless production, the artist having no interest to study perfection, will all his life be satisfied with turning out crude performances. The consumer, therefore, forms the artist by the purity of his taste, and the correctness of his choice ; but institutions form the con- sumer ; and not till a good education. PREFACE. Xlvij the study of the arts, and the sight of good models, have prepared a genera- tion, can we hope to find enlightened consumers. It was long before I concluded what order I should adopt in a Treatise on Chemistry applied to the Arts. I thought at first, that it would be most adviseable to class the arts, and to com- pare their operations for the purpose of going back to principles. But I found that I should lead myself into repeti- tions, and swell out my work to an un- necessary bulk. For instance, as air. fire, water, act in almost all the arts, 1 ghould be obhoed to treat of their ac- tion in discussing each art, and to recur every moment to principles which ha-l Xlviii 1PREFAOE- been previously explained. I resolvetty therefore, in the first place, to establish the genuine principles of the science, and to class under each all the operations of the arts emanating from it ; being convinced, that by following this me- thod all the arts would naturally range themselves under that law which governs their operations* To this end I shall begin with stating the principles of chemistry, and the gene- ral laws obeyed by bodies in their recipro- cal action. I shall then point out the mo- difications introduced in these primitive laws of nature by everacting causes, such as the pressure of the atmosphere, the action of heat, the influence of vitalit}^ the effort of elasticity, &c. PREFACE. xlx After fixing the fundamental basis of all operations considered in the natural order, I proceed to the means which art is capable of employing in its turn, to facilitate or modify the action of these same laws, and to communicate motion to these powerful agents of nature. This first portion of my work, there- fore, embraces not only the knowledge of the laws of nature in the reciprocal action of bodies, but it likewise teaches the means by which the chemist is en- abled to direct, to vary, and to study their effects. Having discussed the general laws of chemical action, and the means employ- ed by the artist, either to apply them to VOL. I. d 1 PREFACE. the bbdies on which he operates, of to calculate the results, it seemed natural to me to follow lip these fundaraental laws, with the description of the princi- pal bodies on tvhich chemical action is exercised ; and I thought it right to ex- hibit them in their highest degree of simplicity, for the purpose of studying the better their peculiar characters. This second part of my work com- prehends the description of earths, of alkalis, of metals, of sulphur, of phos- phorus, of carbon, of the gases, -^c. I have also added the bitumens, the oils, the resins, and the acids, because, though these are compound substances, some are employed as primary materials, while others are in the hands of the che- Preface. 11 mist his principal agents of action, of composition, and of decomposition, and by their combination form compounds the best known, and the most useful in the arts* In these two first parts I have natur- ally been led to notice a great number of arts, and to illustrate their principles. Accordingly, the art of applying heat^ considered with relation to the construc- tion of furnaces, the difference of various kinds of fuel, and the nature of the sub- stances submitted to the action of the fire ; the art of reducing earths to such a state of purity as to render them fit for the purposes to which they are applied ; the art of extracting metals from their ores, and separating them from their d2 iii i»REFACE« natural alloys ; the art of making char- coal, of preparing sulphur, of forming all the acids ; the art of extracting alkalis, oils, mucilages, bitumens, the tanning principle, the juices of vegetables, gela- tine, and of appropriating them to the uses of commerce ; all these objects na- turally found a place in the two first parts. After having unfolded the general prin- ciples of chemistry, and explained the properties and characters of the bodies on which chemical action is exercised, I had nothing more to do than to set these different substances at work, to form mixtures or produce combinations, and to exhibit in one grand picture, the fa- brication of all the chemical products in common use in the arts* PREFACE. liii Following this course, equally simple and natural, I have been led to treat suc- cessively : 1. Of the mixture of gases with each other, which gave me occasion to examine the atmospheric air, and the nature of its principles ; 2. Of the mix- ture of earths, with regard to vegetation, and of their combination in the art of making earthen-ware, glass, &c. 3. Of the alloy of metals, of their oxydation, -and of their reduction, which embraces a great number of operations, and de- scribes many important preparations for the arts ; 4. Of the fabrication of all the salts employed in the manufactures, or used for domestic purposes ; 5. Of the ccnnbinatioTis of sulphur, of oils, of tan, of resins, of coloring p:lKliet has given the appellation of complex affinity to wi at is generally denomi- nated doiihle affinity. It takes place whenever APPLIED TO THE ARTS. 15 a change oF bases is effected by the mixture of two compounds^ each formed of two sub- stances. M. Berlhollet ascribes this effect to the force of cohesion, and observes;, that in all knowa caseSj the strongest affinity has been discovered to reside in those substances, which possess the property of forming a salt that is insoluble^, or may easily be crystallized. Thus sulphuric acid;, which is taken up in any soluble combi- nation, being mixed with a composition that has lime, barytes or strontian for its base^, will produce a change of principles, for the pur- pose of uniting itself to those earths. All soluble combinations of lime, barytes and magnesia, mixed with the carbonates of alkalis effect a change, the result of which is, the precipitation of carbonate with an earthy basis. In all these cases, the force of cohesion^ which is very powerful in bodies that are pre- cipitated or chry stall ized, unites to the affinity, which tends to combine the principles that are to form the insoluble body ; and it is to the ef- fect of this two-fold action that the change which takes place in the complex affinity must be ascribed. 15 CHEMISTRY Tims, when you evaporate a water in whicli you have dissolved various salts liable to change their principles^ you will obtain them in the order of their solubility; and it is by this that you judge beforehand of the changes of\)asis which may take place. SECTION II Of the Modifications produced in Chemical Ac- tion hy Elasticity. There are substances, which, at the tem- perature of the atmosphere, retain an aeriform state, that may be considered as their natural state : so that when you present to those bodies other substances, either for the purpose of pro- ducing a solution, or a combination, you have first to subdue their elasticity. The elasticity of gaseous fluids must there- fore be considered as a resistance to combina- tion and solution, which there are but two ways of overcoming : 1. By an affinity superior to this power of resistance. 2. By a condensation of the gaseous fluid, effected by cooling or compression. APPLIED TO THE ARTS. IT When a gaseous fluid has entered into combination with a body naturally solid, you experience the less resistance in displacing it, in consequence of the tendency to resume its elastic state, which it still retains. SECTION III. Of the ModijicaUons 'produced in Chemical Action hy Caloric. "We have, thus far, considered the modifica- tions produced in affinities by properties in- herent in bodies, such as insolubility, elasticity and cohesion. We shall now direct our at- tention to the influence of a much more ge- neral cause, which seems to be connected with the existence of a fluid univcrsallj^ diffused throughout ail nature, and unequally distri- buted among her various works.* This fluid, * "We here employ the iervnjluid, for the purpose of de- Scribing the eftects of heat, because we are actually con- vinced of tlie existence of a particular fluid, which pene- trates all bodies, is combined with them in greater or less quantity, changes or modifies their corstitution, passes from one to the other, leaving belynd the impression ©f VOL. I. C 15 CHEMISTRY M?Leii coHibiiied witli bodies, is called cahtic : it is this same fluid that, ^vhen set at libeitjj produces heat, and determines the different de- grees of temperature, according to the propor- tions in which it exists. The first effect of this fluid in bodies con- sists in seprarating the particles, and conse- qaently in diminishing the power of cohesion, which holds them together. This fluid may, therefore, be considered as the moderator of the affinity of cohesion ; and the natural constitution of bodies depends only on the proportions which exist between the power of cohesion and thai of caloric. cold or of heat, is probably extracted from all by compres- sion, condensation, &c. which, in a word, has its peculiar affinities, and exhibits all the essential characteristics of fluids. I am aware that philosophers of great eminence consider heat as nothing rnQfe thart the effect of nnotion, and deny the existence «f a distinct fluid. I shall not discuss the reasons on which they ground their S3'stem, because, whe- ther they admit or not the existence of this fluid, is a mat- tthGr p! enomena are then produced. Water at iO degreci;, and water in the state of ice, mixed together iu equal weighty 2^ CHEMISTRY yield a liquid which indicates zevo ; the liquid water, therefore, loses 60 degrees of heat, ■which the ^iid water absorbs in passing to the liquid state. Hence it is obvious, why the thermoiiieter, surrounded with pounded ice^ and plunged into a liquid of a more elevated temperature than ice, continues at zero, as long as an}' ice remains to be dissolved. Liquefaction is not the only circumstance in which caloric is combined and absorbed with- out producing heat. A thermometer plunged into water that is heating, gradually rises til\ ebullition. It then remains stationary, though the heat be increased, provided the evapora- tion be unobstructed ; and it indicates the same degree as long as there is any liquid water left: but as soon as the whole is converted into va- pours, the caloric exercises its full action oij the thermometer, and its temperature rises. From these facts it results, that the caloriq is absorbed, and produces no thermometricaj effect, whenever a body passes from the solid to the liquid state, or from the liquid to the ga- seous state. The caloric absorbed in all cases again makes its appearance as heat, with its vvhole APPI.IED TO THE ARTS. 23 ihermometrical action, whenever bodies return from the gaseous to the liquid state, and from the liquid to the solid state. We may even^ without impropriety, express Caloric by the terms compression, friction, or condensation. These two principles relative to the absorp- tion, or the development of caloric are exceed- ingly fertile in consequences, and afford an ex- planation of a multitude of phenomena which jiature and art present to us in their opera- tions ; such as the refrigeration caused by evaporation, the heat produced by the combi- nation of gases, &c. 4. All the bodies exposed to the same tem- perature are not equally affected by it. Animal and vegetable substances do not acr quire heat till the moment of inflammation, nor liquids till their vaporization. Solids enter into fusion, or evaporate at different degrees. Among the bodies that have just been men- tioned, there are some that become impreg nated w ith heat, but without transmitting it till they have reached the maximum of their saturation. Thus animal and vegetable mat-? ters may arrive at the degree of combustion^, while the bodies near thena shall not be sus- ^4 CHEMISTRY ceptible of the impression of so strong a heat, Metalsj on the contrary^ transmit heat nearly in the same degree that they receive it. From these facts it has been concluded, that bodies are, inore or less, conductors of heat; and numerous applications of this property have been made in the arts. Not only bodies of different natures are not equally affected by the application of the same quantity of heat, but bodies of the same nature receive from it different impressions. Ingen- housz took metal rods perfectly cylindrical, and of equal dimensions; he covered them with a uniform coating of wax, and then plunged the end of each into oil that was near boiling. He observed, that the wax melted at different heights on the different rods, and from these experiments he concluded, that the heat contracted by metals presented them in the following order : silver, copper, gold, tin, iron, steelj lead. 5. Caloric dilates all bodies, but not in an equal degree. In genjial, the same quantity of caloric di- lates elastic fluids more than liquids, and these last more than solids. APPLIED TO THE ARTS. 2^ Liquids differ from each other in regard to their expansibility, which is not proportionate to the elevations of temperature when they ap- proach the state of vapours. In the experiments hitherto made on the di- latation of solid bodies by heat^ no correspond- ence has been found between the dilatations and the quantity of caloric they are capable of absorbing. Nothing but the fusibilit}^ of me- tals seems to coincide with the dilatations ; pla- tina, the least fusible of metals, dilates the least ; lead dilates most, and the most fusible glass is also the most dilatable. We may there- fore lay it down, with M. BerthoUet, as an established principle, that bodies are so much the more dilatable, the less caloric they require to change their constitution from solid to liquid, and from liquid to gases or vapours. From a long series of experiments, Messrs. Guyton and Prieur deduced a dilatation pecu- liar to each gas : but M. Gay-Lussac has de- monstrated, that all gases, without exception^ possess the same dilatability at the same degree of temperature, and that the presence of v.ater in gases occasioned the errors into v/hich his Dredccessors had fallen, i 2G CHEMISTRY M. Gay-Lussac concluded fiom his expeii- ments made on gases reduced to the utmost de- gree of dryness^ that one hundred parts of each of the permanent gases acquired an increase of rhr bj every degree of the thermometer from zero to SO. Vapours follow the same laws of dilatation a^ gasesj provided the temperature be sufficiently elevated to keep them in tlie elastic state. It may;, therefore^ be laid down as a princi- plcj that gases and vapours are equally dilatable and equally compressible, 6. When the caloric escapes from a body highly heated;, without immediately entering into combination, it preserves, for some time, its elastic state, and forms what is denominated radiating caloric. Scheele observed that metallic mirror? reflect radiating caloric without contracting any heat^ and that the air which it traverses likewise re- ceives none : but that, by degrees, the caloric combines, more or less speedily, according to the nature or the colour of the bodies. Gases afford a free passage to radiating ca- loric ; and the more expansible they are, in so much higher a degree ihey possess that pro- perty. APPLIED TO THE ARTS. 27 Liquids quickly absorb it. Black substaiices retaiu it more easily than oihers. 7. A disei^gagement or absorption of caloric is not only occasioned by the changes of con- stitution which bodies undergo, but combina- tions and decompositions produce similar ef- fects. In all the operatigns of which we are treat- ing, new compounds are formed, that present a capacity for the caloric peculiar to them- selves, and must necessarily differ from that of the original com.pounds from which they pro- ceed. When, for example, a gaseous sub^ stance is combined w ith a solid body, the first abandons the caloric which held it in solution, and preserves only what is necessary for the new compound. The operations v/hich produce fixation of the gas, are always accompanied with a more or less considerable emission of heat, according to the nature of the new body that is formed. The simple mixture of two liquids sorhetiraes occasions a pciietration, which may be consi- dered equivalent to a species of combination, and which causes a change of temperatuTQ S8 CHEMISTRY •without altering the nature of the principles. Thus ^yater mixed with concentrated sulphuric acid produces a great heat, and the mixture takes up less space than is occupied by the two separate liquids. Were we to travel through the long series of facts from which result combinations or decom- positions, we should be thoroughly convinced^ that in every one of them there is a production or diminution of heat. SECTION IV. Of the Modifications produced in Chemical Ra- tion 1)1/ Lumic* Besides caloric^ of which we have already treatedj there exists another fluid which fills up * By lumic I mean the fluid \\'hich, when set in motion^ yields light, as we term the fluid of heat caloric. It will doubtless be objected that it has not been proved that light is the effect of a fluid any more than tliat heat is the result of one. This 1 admit ; but as we only direct the attention to tlie phenomena, and as this supposition has no kind of influence either upon the observation or the results, it cannot but appear a matter of indifftrence. My reason APPLIED TO TrfE ARTS. 29 the interval that separates bodies, conveys to our ejes the image of the objects around us^ and has a powerful action on all chemical phe- nomena. Does this fluid emanate directly from the sun, or is it diffused throughout the universe, and set in motion by the rotation of the sun around his axis, and by the collision or brisk action of bodies upon each other ? Be these systems founded in truth or error, the impres- sion of objects transmitted by this fluid is so .speedy, so rapid, that a second is sufiicient to enable the observer to perceive an object at the distance of 80,000 leagues from his eye. The elasticity of this fluid is extreme ; it nevertheless obeys the law of attraction ; for, if you present a piece of steel to a ray of light, the ray deflects from the right line, and inclines toward the body. for adopting it is, that, by means of this supposition, i comprehend the more easily the effects tliat are ascribed to heat and light ; and that, besides, all the properties of those grand agents coincide with tliose which we attribute to fiuids : they are combined or displaced according to inva- riable laws. What more can be required in order to class them among bodies ? 50 CHEMISTRY The influence of light on bodies hai^ evei* been acknowledged. Every person knows that a plant appfears white in obscurity^ that all ve- getables reared in a dark place, seek the light, and incline toward the apertures by which it is admitted : that the only part of fruits which is highly coloured is the side exposed to the light ; that, in a word, the smell, the taste, the com- bustibility, the colour, the maturity, the vola- tile oils, are all products modified in a particu- lar manner by the light. " Were it not for the light," says Lavoisier,* " Nature woiild be destitute of life ; she would be dead and inani- mate. By the creation of light a bountiful Deity has diffused organization, sense, and in- telligence over the surface of the earth.'* If we examine light in a less general point of view, and consider its influence on chemical action, we shall find that it determines various combinations, that it produces decompositions, and that, in many cases, it is disengaged or ab- sorbed consistently with invariable affinities. When bodies change their dimensions, they receive or emit caloric. If these changes take » ■ — — — I I * Traitc EL-iiicntaire de Chiniie, p, 202, APPLIED TO THE ARTS. Sl place with rapidity, they are accompanied with heat and light ; iron becomes hot and luminous by a brisk percussion • oxygenated muriate of potash explodes with sulphur, as do the other bodies that are easily combustible by means of a single percussion, and a considerable quan- tity of light is disengaged. Two flints struck together emit light ; friction exercised on many bodies first produces heat, and afterwards light. We may lay this down as a principle, that, in all the operations which produce heat, it is possible to obtain light by accelerating them. It is even probable, that, in all cases where there is a disengagement of heat, there is also a production of light, with merely this differ- ence, that it is visible to us when the disengage- ment is instantaneous, and that it is not visible "when the production is slow. In this case, it is the same with light as with caloric, which, in the rapid oxydation of metals, and the speedy combustion of phosphorus, determines an ex- treme heat ; whereas this heat is imperceptible to our organs, when the oxydation and com- bustion take place more slowly. It is impos- sible to deny the production of heat in either S2 chemisTrV ca;se : but., in the one^ the emission is instanta-^ Beous ; in the other^ on the contrary^ the sum €5f heat is divided among all the instants of a Terj long interval^ so that its effect is never perceptible. Lumic is not alwajs intimately combined withbodies: there are somethatappearluminous from their nature^ such as phosphorus ; there are others which become luminous at certain periods of tlieir decomposition^ as may be ob- served in various kinds of rotten wood., and certain species of putrid fish. There are also bodies in which the combina- tion of lumic is so weakj that it may be disen- gaged by the slightest friction. The diamond> the biendsj the fluates and phosphates of lime, the Bologna stone^ and the skin of various ani- mals, may serve to establish this truth. Ail bodies are, doubtless, well adapted to the absorption of lumic ; but all do not imbibe it in an equal quantity, nor do all form with it a combination equally solid. There are even some whichj when saturated with light by the rays of the sun, retain for some time the pro- perty of shining in the dark, and lose it by de- grees. APPLIED TO THE ARTS. 33 It appears that all bodies^, without excep- tion^ become red or luminous, when saturated with lumic. Metal, charcoal, earths, nay even liquids, to which jou apply a heat superior to that which is necessary for the fusion of the first, and the combustion or volatisation of the others, all exhibit a red colour. It would seem that, in this case, the caloric and lumic, being no longer able to combine with the bodies which are saturated with it^ become free or ra- (Hating. From all the facts with which we are ac- quainted, the existence of lumic appears to be inseparable from that of caloric : for the ac- tion of caloric constantly produces light ; and when the light is itself collected in the focus of lenses, or reflected in that of concave mirrors, it produces all the effects of accumulated calo- ric. We may be permitted to add, that, among coloured bodies those which best absorb lumic, are also the hottest; and that, in any given case, the stronger the light is, so much the more intense is the heat. Scheele observed, that if you expose to the sun two thermometers in every respect alike, except that one shall be filled with coloured, and the other with unco- VOL. I. D 34 CHEMISTRY loured alcohol, the latter will rise more slowly than the other; but if yoir put the two ther- mometers in cold water, or in the dark, the va- riations of the two liquids are perfectly alike. Caloric and lumic uniformly concur in pro- ducing the same effects ; they are blended to- gether in many phenomena, and appear to be identically the same. But they differ in this point, tliat caloric seems more easy to be absorb- ed than lumic : for example, glasses and trans- parent liquids do not give a passage to radiat- ing caloric, though, at the same time, they suf- fer lumic to pass through them. It appears, therefore, that caloric possesses in a less degree the qualities of eminent elasticity; nay it is even probable that it is endued with less ve- locity. There are certain clieniical eliects, in which heat and light appear to act in a ditierent man- ner. Light, for example;, disengages oxygen gas frcFii nitric acid, whereas heat disengages nitrous gas. Oxygenated muriatic acid parts with its oxygen in the light; but it may be distilled by beat without decomposliion. fsl. Berthoiict, who is inclined to coiisider caloric and lumic as one and the same substance,, dif- APPLIED TO THE ARTS. 35 fering only in the state lo which it happens to he, has collected all the facts which would seem to establish a difierence of nature between these two fluids^ for the purpose of drawing from all their refsults this conclusion^ that there is no difference except in the energy of action. We shall also collect a few phenomena^ in order to throw some light on this subject. Count Rumford impregnated white silk, linen and cotton cloth, and white magnesia, with a solution of gold. Those substances, exposed to the sun or the light of a candle, assumed a beau- tiful purple colour ; in the dark they under- went no change whatever. Scheele observed, that muriate of silver, co- vered with water, and exposed to the sun, emit- ted muriatic acid. M. Berthollet satisfied him- self that the hubbies exhaled from it were no- thing but the air adhering to the muriate, and that the water became acid. He exposed the muriate, turned black by the light, to the action of heat in a small retort : it melted, and muria- tic acid was disengaged. Light and heat pro- duce, therefore, the same efi'ect on muriate of silver. Count Rumford exposed to the light of the 36 CHEMISTRY sun a bottle containing- pieces of charcoal and a solution of gold : the gold was soon reduced ; and a solution of silver experienced a similar reduction. The same effect is produced by putting the solutions into tin cylinders^ and ex- posing them to the heat of boiling water. M. Berthollet repeated the experiment, for the purpose of ascertaining the nature of the gases which are disengaged ; and he obtained a mixture of nitrous gas and carbonic acid. He likewise exposed nitric acid^ into which he put pieces of charcoal^ to the action of light and of boiling water ; in either case nitrous gas and carbonic acid were disengaged. Solutions of gold and silver^ mixed with oil of turpentine and olive oil, are alike reduced by the action of liaht and bv that of heat. In this case, the oil becomes black, because they lose their hydrogen. In the preceding experiments, the effects of caloric and of lumic are the same ; there is no difference wha,tever except in their intensity. M. Ecrthollct also endeavours to reconcile with the same principle the disengagement of oxygen gas from oxygenated muriatic acid, and from nitric acid^ which is effected by the light. APPLIED TO THE ARTS. 37 and not by heat. That difference he ascribes to this circumstance : that, when the acids are engag'^d in one base, they are capable of sup- porting a g-reat degree of heat, and of then yielding oxygen gas, which they never do in the state of acids. Hence he concludes, that the difference of action in this case, is also ow- ing to the intensity of action, and supposes no other difference. Here the lumic combines only with the oxygen, whereas the caloric acts upon all the principles, and tends to volatilize them, "while one opposes no stronger resistance than the other to its action. SECTION V. Of the Moclifications produced in Chemical Ac-^ tion hy the Pressure of the Atmosphere. The atmosphere presses upon all bodies ; and as this force is constat*, it may be considered as a cause which contributes to give each '.ody the constitution that is adapted to it, and which incessantly modifies the efforts of elasticity, and the action of caloric. 38 CHEMISTRY The power of pressure exerfed by the at- mosphere, is equal to the weight of a column of mercury of twenty-eight inches, or of a co- lumn of water of thirty-two feet ; for it is able to raise those two liquids to that height, and to keep them there in equilibrium. In examining the effects of the compression of the atmosphere, Lavoisier remarks, that were it not for this, the particles of liquids would wander at large without any thing to keep them together except their own gravity, which would collect them for the purpose of forming an atmosphere. Mr. Dalton disputes the truth of the asser- tion, that the pressure of the atmosphere keeps water in a liquid state. He observes, that were the weight of the atmosphere to be instantly removed, the aqueous portion which exists in it would not be much increased, because, as he says, it is nearly at the maximum which the temperature is capable of producing and main- taining. The removal of the obstacle would^ in his opinion, accelerate the evaporation, without very sensibly augmenting the absolute qua; tity. Mr. Dalton seems to confound the soluble quantity of water in the atmosphere^ APPLIED TO THE ARTS. 39 with that -vvhich, when reduced io vapour^ would of itself alone form an atmosphere. When we observe that, by a slight dirainu- lion in the pressure of the atmosphere, pro- duced eitlier hy the air-pump, or by ascending to the most elevated points of the globe, we convert ether and alcohol into vapour, and fa- cilitate the ebullition of all kinds of liquids, &c. we cannot deny that, if the atmosphere ceased to press upon the globe, it would be re- placed by the vaporisation of almost ail the liquids with which we are acquainted. By approximating tiie particles of bodies, the pressure of the atmospheric air increases their affinity. M. Biot has demonstrated the possibility of forming v/ater, by subjecting to a violent pressure a mixture of hydrogeh gas ir\ suitable proportions. SECTION VI. Of the Modijications produced in Chemical Ac- tion hij Vitality. The laws of nature are assuredly coistanl 9.nd immutable; and to this their peculiar 40 CHEMISTRY characteristic are owing that uniformity of ac- tion^ and hat succession of phenomena, which renew and perpetuate everj' thing that exists, without the smallest change in the nature of bodies. But when several laws exercise their opera- tive power on the same substa. CC;, and concur in pioducing one and the same action^, the ef- fect, w.sich belongs exclusively to none of them, must be considered as the result of a common efiort, in Wiuch each of the acting laws has a part more or less important. It is in this commixture of powers, in this result of ac- tion, that we must seek to discover how much belongs to each of the acting laws ; the greater is the number of the laws that concur in the ac- tion, so much the'more difficult of solution the problem becomes. Let us suppose, for a moment, that the germs of life ceased to act in nature ; our planet wouid exhibit nothing but masses of matter subject to the invariable laws of gravity and affinities. These laws would determine the ar- rangement of the masses, and the disposition of theii .espective particles. But if we survey this scene of action and of APPLIED TO THE ARTS. 41 reaction^ of composition and of decomposition, which organized beings^ both vegetable and animal, present to our view ; we shall find new agents concurring to produce the same effect, and to modify, ad infinitum, the action of the two primordial laws, of which we have al- ready treated. Every living body is subject io the vital laws of sensibility, irritability, &c. which regulate its functions, and constitute what in it is denomi- nated life : but these laws are not equally nu- merous, nor are they accompanied with an equal degree of intensity or of energy, in the various classes of organized beings. The more nu- merous and intense are these vital laws, the more their phenomena disagree with the regu- lar results presented by their affinities when they operate on inanimate matter. All bodies, without excej?tion, have peculiar affinities, by virtue of which they make choice of certain substances and repel others; but the results of combinations are not alike in all. Y\ hen an earth or a metal combines with other bodies, it changes its nature, that is, the new compound no longer possesses the character- istics of the elements which compose it; thev 43 CHEMISTRY are new beings^ whose nature is still liable to be changed every moment bj the application and combination of new substances. Organic bodies^ on the contrary, have the faculty of ap- propriating- and assimilating aliments^ without changing their natuiC : they impress their pe- culiar character on the substance which serves them for food;, and retain their primitive type without the least alteration. Accordingly, there is a choice of matter and assimilation in organic and living bodies ; they invariably retain their primitive form, charac- ter, and nature ; whereas unorganic bodies are liable to the composition and formation of a new body, whose form and properties cannot be deduced either from the form, or from the properties of the substances of which it is com- bined. If we pay close attention to the phenomena and the results of this assimilation in organic bodies, we shall find that the different degrees of intensity in the vital forces are productive of infinite modifications in them. The more in- tense or energetic are the vital forces, the less powerful is the influence of external agents ou the functions of life. In the vescetable, for in- APPLIED TO TIJE ARTS. 43 stance, tlie principal organs are (^oncealed un- der the epidermis ; they receive, in this posi- tion, the immediate action of heat, of the air and of water, as well as the influence of the internal powers of vitality. These organs exist, if I may so express myself, hctwcen the or- ganic faculties of the plant, and the very pow- erful action of external causes. This function, therefore, essentially depends on the combined influence of vital action, and of the action of air, water/ heat, and light. The plant cannot digest either in a very cold or in a very liot temperature: it languishes in the dark, and withers in too strong a light. Nevertheless it does not receive in an absolute manner the in- fluence or necessary effect of these agents : it has a temperature adapted to it ; it decom poses the water which wets it; it presrrvcs and per- petuates its species, and will perish rather than make choice of and assimilate deleterious sub- stances with itself. But how much more energetic is this vitality in animals : nature has placed their principal organs in the very centre of their bodies, for the purpose of skreening them from the action of external causes. Here all is vital ; and the 44 CHEMISTRY variations of temperature, air, and water, have scarcely any influence on the results. In unoiganic bodies, therefore, there is no- thing but matter and affinity ; all the changes V hicli take place in them proceed from external causes ; the air, water, heat, produce m them effects necessary, constant and invariable. In organic bodies, besides matter and affi' ity, ther- are vital laws which are incessanHv i o- difying the action of external agents, and that of affinity. A view of the effect produced by air, water, and heat, when they act either on a living body, or on the same body when dead, will be sufficient to convince us of the extraordinary power of vitality. We shall perceive that the air and water are subservient to the respiration and nourishment of the living animal, by the decomposition which they undergo in its or- gans, at the same time that heat animates and vivifies all their springs. But after the death of the organic being, these same bodies become the first agents of its decomposition, because, in order to preserve it without alteration, it should be protected from their action. The root of a living plant, plunged into water, de-^ APPLIED TO THE ARTS. 45 composes thai liquid, and derives nourishment from it; but the same root, when dead, and put kito water, is in its turn decomposed. No other proofs are necessary, in mj opi- nion, to produce the conviction of this great truth, that the phenomena and the results pro- ceeding from the action of air, water, and ca- loric, on organized bodies, are essentially dif- ferent, according as those bodies are dead or alive. ^^\e may therefore conclude, that vitality modifies the law of affinities in the living body; or rather, that the action of vitality concurs with that of affinity to produce effects which are common to both. From this incontestible principle it follows, that vitality renders the application of the che- mical laws, deduced from the affinity of dead bodies, the more difficult, in proportion as the living body is endowed with more numerous^ or more energetic vital faculties. In descending from the best organized being to inanimate matter, we find the influence of vitality successively decreasing, and the power ©f affinity gradually rr -niming its empire. We must, not, however^ by any means con- 4i6 CHEMISTRY cliule^ that the law of affinities between the particles of animated matter differs from the law of afiinity between the particles of inani- mate matter. The law is alike in both cases, and affinity is the same with respect to bodies of every description: but it produces con- stant and invariable effects^ when it is to act alone on inanimate matter ; whereas, in living bodies, it,s action is modified by that of the vitaS laws. The laws of vitality not only modify' the re- sults of the law of affinities in a particular and different manner in every class of living beings; but they likewise diversify its effects in the in- dividuals of the same species, and frequently in the same individual, according to its affec- tions, maladies, dispositions, and many other causes which present themselves. We must not, therefore, be surprised, if we find a very great variation in the results of experiments made on living bodies by men equally worthy of credit, and if the observations on vegetation present very different phenomena. The chemistry of living bodies requires a particular and perfectly distinct study; che- mistry alone being incapable of cxplainiug APPLIED TO THE ARTS. 47 any of its funci! ;is. We are acquainted, it is true, with the effects of air, water, and heat, on inanimate matter ; but the observation of the phenomena of living bodies can alone teach us the modifications caused by vitality in all these results. We should consequently involve ourselves in an egregious error, were we to imagine it to be possible to apply and transfer to living bodies the results of action which we observe in dead bodies. Animal chemistry has its peculiar laws, and presents to us results that can nei- ther be foreseen nor accounted for, consistently with the laws of affinity, which we study in inanimate matter. This truth was so deeply im- pressed on the minds of Stahl and Boerhaave^ \vho, to an intimate acquaintance v/ith che- mistry, united a most extensive knowledge of the animal economy, that they abstained from any application of chemistry to the phenomena^ of the human body ; and that the former be- came the founder of the sect of the Animists, and the latter of that of the Mecariicians. For my own part, however, I am far from thinking, that a proficiency in chemistry is either useless or foreign to the study of the 48 CHEMISTRY phenomena exhibited by the living bod}^ Chemistry instructs us in the nature and the properties of ail the bodies that act on the ani- mal economy ; it indicates the alterations the}- experience in their action ; it even furnishes us with the means of discoA'ering and appre- ciating many changes v/hicb take place in the living body. Thus, for example, on analysing the air before and after respiration, we may convince ourselves that a portion of this fluid is absorbed, from which circumstance has been deduced the conclusion, that there is a con- stant production of heat in the lungs. These chemical facts, which are confirmed by physio- logical observation, establish this truth in an incontestible manner. But every thing that is essentially connected with vitality, all that comprises the functions more particularly de- pendent on life, such as chilification, sanguifi- cation, the secretion of humours, nutrition, digestion, the choice of aliments, the effect of medicines, the action ot the organs, can ncithers be explained nor elucidated by chemistry alone. What ^ye have liere advanced must neces- sarily lead to this conclusion, that to acquire APPLIED TO THE ARTS. 49 an accurate knowledge of the functions of the animal economj, it is necessary to combine the analysis of the chemist with the observation of the physiologist. The former makes us ac- quainted with the materials on w liich the vital action is exercised ; it determines their primi- tive nature, and shews their alterations ; it com- pletes, I may say, the labours of the anato- mist, by analysing the organs and the humors which the latter had only separated and describ- ed. But there end his functions, there are the limits of his power ; for hitherto we have ope- rated only on rude matter ; the analysis and the dissection have been exercised only on aii^ inanimate body ; and we have still to prosecute the study of the phenomena, which constitute life in organic bodies. Here observation alone ought to be taken for our guide, because the principle which animates their every particle cannot be subjected either to chemical analysis, or to the operations of the knife. This study is the more difficult, because, if we torture the living body by any means whatever, we cause it to depart from its natural state ; and this being the case, it presents to us nothing but altera- tions. This study is the more difficult, because VOL. I. E 50 CHEMISTRY the principle of life acts, in every function, in unison with laws, complicated from their number, and differing in their intensity, accord- ing to circumstances, in the same individual. Chemistry, in its application to living bodies, may therefore be considered as a science which furnishes new means of observation, and per- mits us to verify the results of vitality by the analysis of its products. But let us beware of intermeddling in the peculiar province of vi- tality. Chemical affinity is there blended with the vital laws which defy the power of art. Above all things, let us not forget, that the part which is reserved for chemical affinity ia all the phenomena of life is the more limited, because they belong to better organized bodies. APPLIED TO THE ARTS. Bl CHAPTER II. Of the Means employed by the Chemist to pre^ pare the Particles of Bodies for Chemical Action. HAVING described tlie laws which govern chemical action^ and the modifications they receive from certain inherent qualities of mat- ter, or from a fluid universall}' diffused through- out nature, it still remains for us to shew the means employed by the chemist in his various operations to dispose bodies to combinations or decompositions. All these preparatory or predisposing means are limited to tlie diminishing of the power of cohesion, which combines the parts of bodies, and opposes their disunion. The means by which we accomplish the diminution of this power are threefold: 1. Mechanical operations. . 2. Solution and crystallization. 3. The application cf heat, e2 52 CHEMISTRY SECTION I. Of the Mechanical Operations employed bi/ the Chemist, to prepare the Particles of Bodies for Chemical Action. When the chemist intends to operate upon a solid body, he first reduces it into an infinite number of smaller bodies, and this division is effected by the hammer, the file, the press, the chisel, or the pestle. He employs one or other of these agents, ac- cording to the nature of the body which is the subject of the analysis. He ufccs the hammer to break stones ; the rasp to divide and pull to pieces roots, fruits, or fresh bark ; the knife and chisel to cut in slices animal substances, and vegetable mat- ters; the press to squeeze out the juices of ve- getable, or the fluids of animal parts. In a laboratory a pestle and mortar are most commonly used, because, exclusive of the ad- "VaP-tage it afibrds of conveniently triturating and pounding hard substances, the form of the APPLIED TO THE ARTS. 53 mortar prevents anjportiou of them from being lost. The nature of the substances which he has occasion to pound, in order to prepare them for analysis, obli2;es the chemist to provide mortars and pestles of different qualities for his laboratory. He must have glass mortars for all corrosive substances^ which are not very hard J mortars of stone, marble, agate, and porphyry, for the trituration of solid bodies, or to bruise herbs, to reduce woods, to pound fruits, and to pre- pare them to receive the action of the press ; mortars of gun-metal, iron, or brass, for all the operations that are performed on such bodies as Oppose a resistance to the action of the pestle. The nature of the body must direct him in the choice of one mortar in preference to another ; and, in this respect, he ought to consult their hardness and their action, that the mortar may resist and not mingle any of its principles with those of the substance he is about to analyse. It is scarcely necessary to observe, that, in order that the matter may be properly sub- jected to the effort of the pestle, the bottom of the mortar must be of a concave form, and so 54 CHEMISTRY adapted to the convex figure of the pestle;, that they be iu contact in every point. The chemist who should merely employ the equal and perpendicular descent of the pestle to effect trituration, would obtain a very imper- fect and unequal division: one part of the matter would necessarily escape pulverization ; whereas by rolling and turning about th^head of the pestle upon the matter, he presses it forcibly against the sides, and successively brings under the action of the pestle, all those particles which might otherwise have escaped the collision. It frequently happens, that the rapid motion of the pestle causes part of the matter to fly off in dust. To obviate this accident, which very frequently produces exhalations, pernici- ous to health, and, which, at all events, are at- tended with some loss of matter, the mortar is covered with apiece of linen cloth, in the mid- dle of which a hole is made to remit the pestle. By this expedient you may prevent all evapo- ration ; but the same end may likewise be an- swered by moistening the substance, when it can be done without inconvenience. There are bodies which it would be very dif- APPLIED TO THE ARTS, OJ ficult to pound, were we not to take the pre- caution to facilitate the process by certain pre- liminary preparations ; for example, ahiiost all stones that are intended for trituration are heated to a red heat, and in that state they are thrown into water for the purpose of cooling them. By this method they are rendered ex- tremely brittle, and may afterwards be broken with ease. There are metals, such as zinc, which yield under the hammer without breaking ; but if zinc be heated, it then breaks with the slight- est effort. When the substance is brought by tritura- tion, to a certain degree of division, you sepa- rate with the sieve all that is sufficiently pound- ed, and throw back into the mortar whatever requires a farther degree of pulverization. By sifting you accelerate the operation, be- cause it is nothing but the fine dust that sur- rounds the un pounded particles, which causes them to escape the action of the pestle. As the sifting occasions a volatilization of an extremely subtle portion of the matter, the re- spiration of which might be pernicious, thi;^ inconvenience is obviated by employing a sieve i)b CHEMISTRY iiomposed of three parts^ tba is, of the sieve it- self, a cover and a receptacle underneath. In this case, you put the matter into the sieve, to which you then affix the receptacle and the coverj and proceed to the operation. The pow- der passes through the sieve into the receptacle,, out of which it is taken when the operation is finished. By adapting to each other several sieves, the holes of which are of different dimensions, and by placing them over one another, in such a manner, that the sieve with the largest holes shall be uppermost, and that with the smallest holes lowermost, you may obtain, by one and the same operation, several products of different sizes. It is in this manner that the different kinds of shot for the sportsman are separated. Another operation performed by means of water may be substituted for that of sifting. The pounded matters need' only to be shaken in that liquid ; they immediately settle at differ- ent heights, according to their division, be- cause the largest precipitate themselves first This process is employed in the arts to obtain certain preparations at various degrees of fine- ness. As they are generally broken by the aid APPLIED TO THE ARTS. 57 of millstones which move in large tubs full of watefj the motion of the stone agitates the par- ticles, the lightest of which ascend to the top of the tub, while the coarsest remain under the stone. By turning cocks, fixed at different heights, and drawing off' the liquid that is above them, all the degrees of fineness that are required may be obtained. In some other operations of the arts a cur- rent of water is made to pass over the matter subjected to the action of the pestle : this wa- ter successively carries away all that is suffi- ciently divided to be removed. It runs into a series of reservoirs, where it deposits, more or less speedily, what it has carried away ; so that the first reservoirs retain the coarsest matter, being the heaviest, and the last receives only the finest and most subtle portion. Washing is employed, not only to separate homogenous matters, differing only in their de- gree of division; but it likewise ajibrds the means of separating matters of the same degree of fineness, and of different specific gravit}^ It is more particularly in the operations of the mines that these methods are employed for the 5S CHEMISTRY purpose of separating the ore^ or the metals, trora the stones with which they are united. Porph^Tisation is nothing' but a more com- plete trituration. It is performed on a flat piece of porphyry, or any other stone that is very hard, and has a very smooth surface, with the aid of a stone of the same degree of hard- ness, which is called a mullar. The matter is spread out upon the slab of porphyry ; you then take the mullar with both hands, and work it circularly, and in different directions, to grind the matter. That part of the mullar which comes in contact with the porphyry, must not be perfectly flat ; its surface should be a portion of a sphere with a very large radius; otherwise the matter would be driven before the mullar, and could not get underneath it to be ground. When the matter is too much spread on the surface of the porphyry, it may be brought back to the centre, by means of a knife with a very thin blade of iron, horn, or ivory. Before the chemist begins to operate chemi- cally upon any substance, he determines its weight; and the means he employs belong to APPLIED TO THE ARTS. 59 tlie series of operations preparatory to chemi- cal action. Whenever he wishes to determine the quan- tity of matter which a hody contains, he ha- lances it against other bodies whose weight he knows, and which he takes for the term of com- parison. The instrument which is most commonly used is an iron lever, suspended by the middle, so that the two arms shall be suspended in equi- librium, and possess the power of a free ascent or descent, with as little friction as possible. These instruments are termed halances, or scales. But in the various circumstances in which the chemist lias occasion to determine the weight of bodies, two objects present them- selves. The first is, to determine the weight of a mass, and the second, to compare the respec- tive weight of a given volume of that mass, with alike volume of other known bodies. In the first case it is the ahsolute 'weighty and in the second the specific tue/g/zf, that is sought. When he is about to determine the absolute weight, he has either to weigh large volumes. 60 CHEMISTRY or small objects ; and employs large or small scales accordingly. A laboratory should be provided with scales of extreme precision ; for as the chemist ope- rates there only on small masses, and as he fre- quently extracts, by analysis, some atoms whose weight it is always of consequence to appre- ciate, he ought lo be provided with instru- ments of extreme nicety for that purpose. Be- sides, it is almost always on the results of ana- lyses that we decide either to work a mine, or to engage in other important undertakings : so that it must be evident of what consequence it is to avoid every cause of error. As there is often occasion in laboratories to weigh salts, acids, and other corrosive matters, the chemist is obliged to put them «p in glass vessels; and it is then indispensably necessary to weigh separately the vessel that contains them, to deduct that weight from the total weight, which leaves that of the liquid. This double operation is attended with a great loss of time ; and I obviate this inconvenience, by using two glass capsules of the same weight, moveable and deep, which arc placed in the APPLIED TO THE ARTS. 61 two basins of a pair of scales, and which may be taken out at pleasure. The scales should hang in a dry place, in a good light, and out of the reach of the corro- sive vapours of the laboratory. Without this precaution they grow rusty, and become spoil- ed. The most delicate should be kept in glass cases, and should not be taken out without oc- casion. If the chemist has to weigh gases, it is ob- vious that it w ill be necessary to make certain modifications in the processes above described. And as he is obliged to inclose in vessels the li- quids whose weight he wishes to know, so he is also necessitated to shut up aeriform substances. For this purpose he has a large globe, contain- ing at least one cubic foot, that is, sevo^iteen or eighteen quarts. This is affixed to the plate of the air-pump, and it is emptied as much as possible, the operator taking care to observe the height to which the barometer gage descends. When empty, the cock affixed to the covering of the neck is shut, and the globe is weighed >vith the most scrupulous accuracy. It is then screwed on a bell which contains the gas that is to be weighed, and which stands on the table 62 CHEMISTRY of the hydi'opneumatic tub. It is sufficient to open the cock in order to determine the ascen- sion of the gas into the receiver ; it is neces- sary to plunge the bell into the tub^ so that the water on the outside may be on a level with that \\^iich is within. The cock is then shut^ the globe unscrewed, and again weighed. The weight, deducting that of the empty globe, gives the gravity of the volume of gas which it contains. Multiply the weight by 1728, and divide the product by the number of cubic inches equal to the capacity of the balloon, and vou have the weight of a cubic foot of the gas which is the subject of the experiment. To reduce the weight of the cubic foot to that which the same gas would have under a pres- sure of twenty-eight inches of mercury, and at a temperature of ten degrees of the thermo- meter, employ the process detailed by Lavoi- sier in his Elements of Chemistrij. You must by no means neglect to take into account the small portion of air left in the globe ; it is estimated according to the height at which the barometer gage stood. If that height was, for instance, t^o of the total height of the barometer, you may conclude that t6s APPLIED TO THE ARTS. 63 part of air remained in the globe, and that the total volume of gas was no more than r^ of the total volume of the globe. On these principles Lavoisier drew up the following table of the weights of different gases, at a pressure of twenty-eight inches, and at ten degrees of the thermometer. Weight 1 Names of Weight of a authors who Names of gases. of a cubic inch. t5 cubic foot. ascertained the weights. Grains. oz. dwt. gr. Atmospheric air - 0,46005 1 3 3,00 Lavoisier. Azotic gas 0,44444 1 2 48,00 Lavoisier. Oxygen gas 0,50094 1 4 12,00 Lavoisier. Hydrogen gas - - 0,03539 Gl,15 Lavoisier. Carbonic acid gas - 0,68983 2 40,00 Lavoisier. Nitrous gas 0,54690 1 5. 9,14 Kirwan. Ammoniacal gas - 0,27488 6 43,00 Kirwan. Sulphurous acid gas 1,03820 3 66,00 Kirwan. By specific graviiy is meant the absolute weight of bodies divided by their volume ; or, what amounts to the same thing, the weight which any given volume of a body weighs. But, in order to have a term of comparison. 64 CHEMISTRY the weight of which shall be invariable, and wliichj consequently, maj^ be taken for the unit to which the weight of the substance that is the subject of the experiment is re- ferred; distilled water has been chosen as the body whose gravit} ., when of the same volume, is not liable to variation. Thus the weight of the water being represented by the number 1, the weight of an equal volume of gold will be represented by 19. In areometry, therefore, the whole business consists in obtaining the gravity of a body compared to that of a similar volume of dis- tilled water. The methods varv accordinji: to the constitution of bodies. To find the weight of a solid, insoluble in water, it is weighed first in the air, and then in water. By deducting from the total weight what it has lost in the water, you have its gra- vity compared to that of an equal volume of water. This process is grounded on the two following principles. 1 . That a body plunged and immersed in a liquid displaces a volume of water equal to its own. APPLIED TO THE ARTS. CO 2. That (lie \veig;lit of the water displaced is equal to that which the body loses in its im- mersion. When solids are lighter than water, we em- ploy for the purpose of immersing them^ a body whose gravity in water is already known, and wliich we deduct when we determine, by calcu- lation, the comparative weightof the solid. The simplest instrument for weighing solids is a balance, from one arm of "vvhich the sub- stance is suspended by a very fine thread. You first weigh the body in the air, and afterwards in water ; and deduce, from the diflerence, the weight of the vohime of displaced water to be equal to that of the body, Mr. Nicholson's scales for solids are the most portable. This instrument consists of a glass or metal cylinder, from the extremity of wliich is suspended one of the scales. The other is placed at the upper part, and affixed to a very small shank. You lay the body to be weighed upon the upper scale, and keep adding weights till it descends to a certain mark. Compare, these weights with those which are required toi make the instrument descend to the same mark ; VOL I, , F 66 CHEMISTRY and the difference gives the absolute weight of the body. Then place the body to be weighed in the lower scale ; charge the upper with weights till it descends to the mark : and vou have the weight of an equal volume of water upon deducting from the total weight that which you have just added. M. Guyton has improved this instrument by adapting it to the weighing of liquids as v*ell as solids. He has iidded to it a piece which he calls a plunger, because it is designed to be placed in the lower scale. This plunger is a glass ball, ballasted with a sufficient quantity of mercury to reader its total weight equal to the constant additional weight, and likewise to the weight of the volume of water which this plunger displaces. When you have occasion to weigh liquids of less specific gravity than water, you know the weight of the instrument in water, which you compare with its weight in the lightest liquid. In the case of a very heavy liquid, besides the plunger, you put weights into the upper scale to sink it down to the mark. It is unnecessary to observe that this instru- APPLIED TO THE ARTS. 67 ment can only weigh such bodies whose weight does not exceed the additional weight necessary fof sinking the gravimeter to the mark. Various instruments^ more or less proper for determining the comparative gravity of liquids, have been at difl'erent times proposed. 1. Weigh an empty bottle; fill it with dis- tilled water, and weigh it again ; pour out the water, and replace it w itli an equal volume of the liquid whose comparative gravity you wish to ascertain ; if you deduct in both cases the weight of the bottle, it is evident that you w ill have the comparative weight of the two liquids. This is Romberg's process. 2. Plunge into distilled water a body which is unassailable by that liquid ; load the body with different weights to sink it to a fixed and determinate mark on a standard to which it is affixed. Knowing the weight of the instiU- ment, and those which were required to de- press it, their sum gives the weight of the wa- ter displaced. Plunge the same instrument into the liquid whose gravity you wish to ascer- tain ; charge it with weights, to sink it to the same mark, and the sum total of the gravity of the instrument, and of the added weights, gives f2 (jS chemistry the weight of the liquid displaced. This weigh! compared to that of an equal volume of dis- placed water, forms the comparative gravity. This is Fahreuheit's areometer. 3. The simplest instrument for weighing li- quids, or determining their degree of concen- tration, is Baume's areometer. It consists of a graduated glass tube, ballasted at the lower end by a small quantity of mercury, which keeps it continually in a vertical position. Wli€n plunged into distilled water, it stops at the point marked zero : the upper graduations ex- press the diiferent degrees to which it sinks in the lightest liquids ; the lower mark the de- grees to which it rises in the heaviest liquids. This instrument is convenient for use; and though it does not present a mathematical pre- cision, it serves for the ordinary purposes of our manufactures, in which scarcely, any other is employed. 4. Mr. Rarnsden proposed a very small pair of brass scales with unequal levers, with a weight running on one of them after the man- ner of the Roman steel-yard. At the end of the other arm is a fine cord of horse-hair, from which is suspended a glass ball ballasted with APPLIED TO THE ARTS. 69 mercury. The gravity of liquids is estimated by the weight which the ball gives when it is immersed. Instead of the hair-cord it is ad- viseable to use wire of platina.* It is scarcely necessary to observe^ that in or- der to appreciate the specific gravity of fluids with great precision, it is necessary to take ac- count of the temperature of the atmosphere, which, by dilating them more or less, produces a variation in the instruments. Those, how- ever, which we have described above, are suf- ficient for ordinary purposes ; and it is unne- cessary to estimate the temperature, except in regard to the most evaporable liquors, or those in which the smallest diHerence in consistency- is productive of great variations in commerce. Hence it is that in the sale of ardent spirits and alcohol it has become customary to calculate the degree by the application of the thermo- meter and areometer. In the Memoirs of the Society of Sciences of Montpelier may be * On this subject consult the Memoirs of M. Hassenfratz, Chemical Essays on Areomctry, and Bmson on Specific Gra^ Vities, 70 CHEMISTRY found a series of ingenious experiments on the mixtures of water and alcohol, and on the di- latability of those mixtures at various degrees of temperature. In conformity with the re- sults of these experiments was constructed the spirit-gage employed in the south of France to determine the degrees of strength of ardent spirits, which is accompanied with the correc- tions adapted to different degrees of tempera- ture. SECTION 11. Of Solution considered as a Medium prepara- tory to Chemical Action. We call solution the division and disappear- ance of any kind of body in a liquid, without either of them undergoing any alteration in its nature. We adopt this term in the sense given to it by the celebrated Lavoisier,* and with the * Elementary Treatise on Chemistry, vol. ii. chap. 5, sect. 1. APPLIED TO THE ARTS. 71 greater justice^, as that operation is essentially different from dissolution, which ought to be employed only to explain the action of an acid on a metal, an earth, or an alkali. In the latter case, there is not only a solution, but likewise a combination, and sometimes a decomposition of one of the bodies, as when an acid is made to act on a metal, or on a neutral salt, the acid of wliich may be displaced by the more power- ful acid which is employed.* From this distinction between solution and dissolution, established by Lavoisier, it follow s, that the term dissohrnt cannot be applied to the liquid which determines the solution ; ia- * As this chapter treats only of an operation preparatory to chemical action, it is obvious that it would not be proper to consider, in this place, the dissolution which is attended with combination or decompontion. It cannot but excite astonish- ment that as the results of solution and dissolution are so dif- ferent, those operations should have been expressed, down to the time of Lavoisier by one and the same word. In the language of the sciences, in particular, we should be care- ful not to apply the same denomination to opposite results or operaiioiis totally distinct from each other. 72 CHEMISTRY stead of it we must necessarily substitute the word resolvent. Thus the resolving body is the liquid in which the body that is resolved dis- appears; and to express ourselves in a more general manner^ we shall say with M. Monges, that the resolvent is the body which preserves its form^ and gives it to another. There are bodies whose constitution is such that they constantly appear in a liquid state^ at the ordinary temperature of the atmosnhere : in this class we place the i^esolvcnts, such as water, alcohol, caloric. Bodies naturally solid or gaseous may be re- duced to a liquid state, if we increase the quan- tity of caloric in the first, or diminish it in the second. Their power of cohesion and elasti- city determine the quantity of caloric which must be added or subtracted to produce that If certain solid and fluid bodies have hitherto withstood solution, the reason is, because we have not been able to apply to the one, a,nd take away from the other, the quantity of ca- loric necessary to break their cohesion. When the force of cohesion cannot be over- APPLIED TO THE ARTS. 73 come bj the affinity of the resolvent, the che- mist employs three methods of preparing the body for its solution. 1. He weakens the power of cohesion by mechanical means. 2. He increases the affinity of the resolvent by the concurrence of caloric. 3. He diminishes the cohesion by saturating a portion of its energy by the addition of an- other body. The division of a body is attended with the twofold advantage of diminishing the cohesion and of multiplying the surfaces; it weakens the resistance and increases the action. Lime- stone and quartZ:, naturally insoluble in water, may be reduced to such a degree of tenacity, as to be carried away by that liquid and slowly deposited ; on which their particles reuniting assume regular forms. In this manner we may account for the formation of rock-crystals and calcareous spar en rocky surfaces continually wetted by water which has run through rocks of a nature analogous to that of the crystals. Bergmann observed, that bodies w^hich are not sensibly attacked when they are in a mass, become soluble when tliey are divided. 74 CHEMISTRY The action of affinity may be further assisted by means of caloric. It has the two-fold ad- vantage of diminishing the cohesion, and of being itself a resolving body ; so that when- ever caloric is employed in conjunction with another fluid, a complicated effect is obtained from the action of the two agents ; and, in or- der to form a correct idea of the share which caloric has in the result, we ought to consider it in the two points of view under which we have just exhibited it. 1. It weakens the force of cohesion by separating the particles ; this effect is suiScientto determine the action of the resolvent in many cases, and contributes to ac- celerate it in all, 2. It dissolves of itself apart of the body, in proportion to the quantity in which it is employed; refrigeration alone, or what amounts to the same thing, the subtrac-' tion of this cause of solution, occasions the pre- cipitation of all that portion of the body which owed its solution only to the caloric. It must not, however, be imagined, that ca- loric, in every case, facilitates solutions. This property of caloric is incontestible only when it acts on fixed bodies, whether solid or li- quid ; for when you operate on bodies whos« APPLIED TO THE ARTS. 4D natural state is that of an aeriform fluid, the caloric then facilitates the action of that power of elasticity, which is incessantly tending ei- ther to reduce those fluids to the state of gas, if they be in combination ; or to keep them in that state if they possess their natural expan- sion ; so that in all these cases, caloric tends to develope and to strengthen the energy of elasticity, which is incessantly counterbalanc- ing that of affinities, and resisting the action of resolvents and of dissolvents. A third method, which is employed to pre- pare bodies for solution, consists in diminish- ing the force of cohesion by the combination of another substance. An example will render this perfectly intelligible. When you throw quick-lime into water, the lime attracts and absorbs it; but as it becomes saturated, its force of cohesion decreases, so that, at length, the affinity of the water prevails, and it dis- solves a small portion of lime. Sometimes there is so little affinity between a liquid and a solid, that the latter is not sen- sibly wetted by the former, and that the liquid stands in large round drops upon its surface. Of this water and tallow afford an example. 76 CHEMISTRY Sometimes, on the other hand, the affinity of the resolvent so completely overcomes the re- sistance of cohesion opposed by the body to be resolved, that it is impossible to preserve to the latter its solid form, except by removing it from the contact with the resolvent. It is this facility, this tendency to solution, which con- stitutes the character of the class of salts deno- minated deliquescent ; because, when thej' are exposed to the air, ihey draw from it the small portion of humidity requisite for their solu- tions. Dr. Watson, who has most attentively ob- served the phenomena of solution, has de- duced from his numerous experiments these conclusions : 1. That w^ater acquires volume at the mo- ment of the immersion of a salt. 2. That its ^olume decreases during the dis- solution. 3. That it ascends, after the dissolution, higher than its original level. The first phenomenon is the necessary effect ofthe immersion of a solid in a liquid. The second is the immediate result of the lowering of the temperature produced by the solution. APPLIED TO THE ARTS. 7 7 The third indicates that the liquid, on reco- vering its temperature, is restored to its natural state, with a sensible augmentation of volume, in proportion to the volume of the body with which it is charged. Nevertheless the aug- mentation of volume bears no proportion to that of the body resolved, which announces a kind of penetration^ or of combination between the two bodies. The operation of the solution of salts in water invariably produces cold. Messrs. Fourcroy and Vauquelin have, it is true, in- structed us, tliat when the water of crystalliza- tion is separted from the salts which require a great quantity in order to crystallize, their so- lution in water is attended with a disengage- ment of caloric ; but then those salts are lao longer in their natural state ; and they produce cold, like all the others, when they are resolved with all their water of crystallization. \\ hen the water holds a salt in dissolution, the new body may then be considered as having particular affinities, distinct from those of thi* two bodies which compose it. Thus the solu- tion of alum in water, parts with a large por- tion of alumine, which precipitates as soon as the alum of crystallization is disengaged. iS CHEMISTRY When a liquid holds several salts in solu- tion^, evaporation or lowering of the tempera- ture precipitates them in an inverse ratio to their affinities with the resolvent. These salts are seldom separated perfectly pure^ because the J exercise mutual affinities, by virtue of which they unite and commix more or less. Two liquids are likewise subject to be resolved when their respective affinities are stronger than their powers of cohesion. If water and ether be mixed in equal parts, they form two liquids which remain separate ; the one below, composed of much water and little ether; the other above, consisting of a small proportion of water and a large quantity of ether. Solution may be accelerated by slightly agi- tating the liquid ; for, by this expedient, the water, whose affinity is weakened, is succes- sively displaced, and makes room for a more eager portion of the same liquid. The mo- tion has likewise the advantage of producing on the surface of the body that is intended to be resolved, a mechanical fiiction, which de- taches some of its particles, and gives them up to the action of the resolvent. As it is of consequence in many of the arts. APPLIED TO THE ARTS, . 79 that liquids should not evaporate till they are nearly saturated with the body that is operated upon, the same liquid is passed, at several times, over fresh quantities ofthcbody to be resolved^ and is charged with it till it arrives at the re- quisite degree of concentration. The same re- sult is obtained by causing the liquid to pass through avery thick bed of the body which it is intended to resolve, and leaving the two bodies in contact long enough to produce saturation. SECTION in. Of Crystallization considered as a Medium pre- paratorij to Chemical Action. The object of almost all salutions and eva- porations is to concentrate liquids, in order to effect the crjstallization of the salts which are dissolved. The particles which are thus con- centrated have a continual tendency to assume polyhedral, constant and determinate forms. The regularity of the forms is a law of mat- ter as general as that of a-ravitv. ' Nature has impressed on every class of bodies an invariable form, and it is this variation in So CHEMISTRV form that draws the principal line of demarca- tion between them, and that enables us to dis- tinguish them at the first sight. It is this property, possessed by all bodies, of affecting an invariable form, that chemists have termed crtjstallization. In organic beings the form appears to be most generally adapted to the wants of the liv- ing body ; but in mineral substances it seems to be a matter of indiflerence. The first chemists who discovered that the figures of bodies were almost invariably the same, denominated crvstals after the resem- blance more or less rude, which they thought they perceived between them and known bodies ; hence the name of crystals in the form of tombs, diamonds, crosses, knife blades, &c. These expressions, which referred only io bodies whose figures are extremely variable, conveyed but very confused ideas to the mind. The celebrated Linn.TUs appears to have been the fir&t who ascertained that all these forms were geometrical ; this led him to imagine, that he might make it the basis of the metho- dical distribution, or classification of mineral substances. Applied to the Arts. Bl kome de Lisle submitted all the known forms to a strict examination, and was of opi- nion that Ire could discovcfj in the great variety of figures presented by the crystals of the same species of body, a primitive form, of which the others were but modifications. By dividing crystals by mechanical means, M. Haiiy has demonstrated the existence of a primitive nucleus in each crystal. This nucleus has an invariable and determinate form for each kind of body, but the successive applica- tion of new lamina produces infinite modifica- tions in it. That celebrated mineralogist has sliewn in what manner these lamina, superad- ded to the primitive form, are capable, by their decrease, of varying, modifying, and changing it His works leave nothing but the impres- sion of truth on the minds of all those who are seriously engaged in the study of crystallo- graphy. Accordingly, hydividing an hexahedral prism of calcareous spar by sections parallel to each other, you may remove, successively, all the lamina in which it is enveloped, till you come to an invariably uniform nucleus, which repre- sents a perfect rhomboid. By breaking off the TOL. I. fl S2 CHEMISTRY" eig-litsolrd angles of a cube of fluor spar, voil obtain an octahedron. The ponderous spar vvi]I produce an upright prism with rhomboidal bases ; feld-spar an oblfque-anoled parallel- opipedon ; the bervl, an uprii^ht hexahedral prism ; adamantine spar^ a somewhat acute rhomboid ; blend, a dodecahedron with rhom- boidal surfaces ; iron of the island of Alba^ a cube, &c. If, after coming to the last subdivision, you were to aUeii-ptlo proceed in the same mannei' in other directions, yau would break the crys- tal instead of dividing it. But the solid which forms the nucleus may also be subdivided in a direction parallel to its faces. The same is the case with respect (o the enveloping matter, which may be divided by sections parallel to the faces of the original er3stal ; so that the detached parts are similar to each other, diil'cring only in bulk, which keeps diminishing the longer the division is continued. It is these small similar solids, susceptible of an extreme division, that form the integral particles of crystal. Having ascertained the primitive figure of the crv'ital, and consequently that of its inte- Applit:d to thr arts. 85 ^ral particles, the next point was to enquire for and determine the laws, according to which these particles arranged themselves, in order to form around this nucleus, a covering which should pl'esent polyhedrons very different from each other, though originating from the same sub- stance. Now M. Haiiy has demonstrated, thai all the parts of this covering are formed of la- mina, which decrease regularly by subtractions of one or more ranges of integral particles. Thus, for example, by raising on each face of a primitive cube a series of pyramids, each of Mhich is diminished by a range of small ele- mentary cubes, you will obtain a decahedron ; and the cube, before it arrives at that form, will pass through a multitude of intermediate figures ; so that, if the work of nature stops at one or the other of these passages, you will have modifications in the primitive form. As the diminutions are formed by lamina^ whose particles are very diminutive, the faces of the pyramid are exceedingly smooth. But if the courses of the pyramid decrease in a greater progression, that is, if instead of a range of cubes, there is a subtraction of from four to six from one course to another, the pyramids r '■^ Si CHfiMIsTRY will be more elliptical, and as their adjacerfi faces can no lon2:er be level, the surface of tlie secondary solid will be composed of twenty-four isosceles triangles inclined over one another. The diminutions of the superincumbent la" mina take place, in general, in a direction pa- rallel either to the edges of the nucleus, or to the diagonals to the former. M. Haiiy has given the appellation of diminutions on the edges, and io the latter that of diminutions on the ajigles. There arc some rare cases in which 4hese diminutions are mixed. Sometimes the diminutions take place on all the edges, as in the dodecahedron with rhom- boidal sides mentioned above ; sometimes in all the angles, as in the octahedron, from which the Cube originates ; sometimes only on cer- tain sides, or certain angles. Sometimes the diminutions are uniform, both on the edges and on the angles. At others they vary from one edge to another, or from one angle to another ; this happens more par- ticularly when the nucleus has a symmetrical form, and when the faces dilfer^ for example, by their respective inclination, or by the mea- sure of their angles. In certain cases, the di- APPLIED TO THE ARTS. 85 minutions on the edges concur with the dimi- nutions on the angles to produce one even crystalline form. It likewise happens^ some- times^ that one edge or one angle is subject to several laws of diminution which succeed each other. The number of subtracted ranges is not, in general, very variable ; the subtractions are most frequently formed by one or two ranges of particles, and this decreases the number of forms which might be produced by the dimi- nutions. If there were diminutions bv ten, twenty, thirty, or forty ranges, as might be pos- sible, the prodigious variety of forms would be sufficient to startle the imagination. But not- withstanding the narrow limits by which the laws of crystallization are bounded, M. Haiiy has found, by confining himself to the two most simple laws, that is, to those v>hich produce the subtractions by one or two ranges, that cal- careous spar is susceptible of 240,000 different forms, and of 8,388,60 1^ admitting diminu* tions by three and four ranges. The stripes or grooves which appear on the surface of most crystals are always parallel to the borders of the superincumbent lamina. 83 CHEMISTRY These points, or ihe-^e inequalities in the work of crystallization, announce th^,t nature has not been i.. tull possession of the conditions ne- cessary for pGi lectin^ her operation ; bpt these apparent aijonialies become a new proof of the diminution of the lamina. The fecundity of the lavs upon vyhich de- pend the variations of crystaUtne forms is so g.eatjthat frequently particles of various figures arrange tb.emselves in such a man per as to form similar polyhedrons in diftcrent kinds of mine- vals. Thus the dodecahedron, v, ith rhomboidal sides, which may be obtained by combining cubic particles, proceeds in the garnet from small tetrahedrons with isosceles-triangular faces. It is likewise possible, that similar par-, tides may produce the same crystalline form by dift'erent laws of diminution ; and there may exist, by virtue of a simple law of diminution, ^ crystal which may externally resemble the nucleus, that is, a solid resulting from nqnq of the laws of diminution. M. Haiiy has reduced to six primitive for.mj all those which mechanical analysis presented to him in the dissections of crystals. These forms are the parallelopipedon in general. APPLIED TO THE ARTS. 87 wliich conipreiuMuls t!ie cube, the rhomboid, and ail the solids teraiinated by six parallel faces two and two ; the regular tetrahedroi: : the hexagonal prism ; the dodecahedron with rhomboidal sides^ and the dodecahedron with isosceles-triangular sides. This able crjstallographer further observed, that the identical forms which have hitherto been found as nuclei in the different species, belong to those that possess a particular charac- tf^r of perfection and regidariij ; as tbe cube, theregular octahedron, the regular tetrahedron, the dodecahedron, with rhomboidal, equal and similar sides. These forms, which belong to difierent species, may be considered as the li- mits at which nature arrives by djlFcrent ways, while each of the figures placed between these limits seems to be confined to one particular fpecies. It now remains for us to shew what condi- tions are necessary for bringing a body to a perfect crystallization. 1. A body does not crystallize, unless, by ft previous division, the cohesion is broken, and the particles are enabled fully ai^d freely to ^x- pr^ise their reciprocal affinities. 88 CHEMISTRY This division may be effected bv solution ? the .soiulioiiis operated in water for sails in ca-f loric forviiineralsj and ia alcohol for resins and certain oils. 2. When a body is dissolved in one or the other of the^c lluids, the reunion of the parti- cles dissolved is effccte-d by evaporation, or by lovsering the temperature of the liquid. In the cases in which the solution is per- formed by water or alcohol, evaporate till small crystals are formed at the surface or on the sides ; then suspend the operation, and as the liquid cools, a great quantity of salt in crsslais is precipitated. By evaporating- the liquid which remains, after removing the crys- tals on the top, you may obtain a second quan- tily of crystals, and extract the liquid from all the salt by successive operations. But if the dissolution is effected by caloric alone, as in metallic fusions, and those of sulphur and phos^ phorus, other precautions are necessary to de- cide the crystallization. If you suffer a melt- ed metal to cool, it will not fad to appear again,, in consequence of the refrigeration, with its primitive form, exliibiting, at the same timCj, spine confnsed traces, or imperfect lineaments APPLIED TO THE ARTS. 89 of crystallization, such as are observed in an- timony and zinc. But if, at the moment when the melted metal begins to harden, you pierce the crust, and let cut the metallic liquid contained within, the vacancy v. ill be liiied with regular crystals^, which almost always pre- sent the cubic or octahedral form. Hence we may infer, that the metal in a mass is nothing but an aggregation of crystals, and th.at the only method of giving it the requisite cohc-ioa and ductility, is to beat it Vv-ith the haiiuiier, and to TCT/rZ it. From svhat has been said concerning cry- stallization eftectec' by evaporation and refiige- ration, we may conclude, tliit, after having sa- turated a boiling liquid with any saline sub- stance whatever, nothing more is necessary to obtain a deposit of crystals than to let it cool. Vf e shall easily comprehend all these pheno- mena, if we consider, that there are then two liquids acting upon the salt ( water and calo- ric ) ; and that, by taking away one of them, we cannot fail of having the whole of the salt which it held in dissolution for a precipitate. When the evaporation of the dissolvent prcn 90 CHEMISTRY Cfeds slowly^ the crystallization is always more r^^gular ; tlie j)asticles then unite and arrange tiioiiiselvcs by virtue of their affinities; but, on t|ic contrary, when the evaporation is rapid, the particles are precipitated upon each other, and there is nothing' but confusion in their assem- bliige. The slowness of the evaporation not only determines the regularity of the forms, but likewise contributes to give volume to the cry- stals. This we observe daily in the saline solu- tions which we leave in a corner of our labora^ tories ; this is demonstrated by all the opera- tions of nature, who forms in time, and by in- sensible evaporation, saline and stony crystals, vhich it is impossible for us to imitate, because }t is not in our power to cause ages to enter as elements into our operations. Rest is equally necessary for the liquid, in order to obtain forms of great regularity : un- interrupted agitation prevents all symmetrical arrangement; it precipitates the crystals as fast sjs they are formed, and you obtain nothing, if I rnay so express myself, but the integral parti- 4:le::^ of crystals. APPLIED TO THE ARTS. 9\ Wc avail om.selvcs in the arts of the distufr. bance produced by agitation in liqnifis to pro- cure crystals of extreme Hneuess. It is by tins i|ietliod tbat vve precipitate, in \ei'y snnall and delicate needles, the crystals of sul^'hate of sodaj those of nitrate of potash, &c. It freqiicntly hapoens that a dissolntion, though complete, refuses to crNstalHze ; in this case a slight agitation of the vessel somelinics decides the crystallization. Fahrenheit ob- served, that, in this circiunstance, heat escaped at the moment of agitatioTs, whi; h seems to prove tliat the caloric was interposed between the particles, and that nothingbut the slightest inotiou was wanting to disengage it. A cry star formed in water always retains a raore or less considerable portion of the liqriiaji |ind this is called the zcatcr of crystallization. The only cause of solution is, that the affi- nity of the liquid overcomes the cohesion which connects the particles of the salt ; but lu pro- portion as the ma^s of the liquid diminisncs i y evaporation, its affinity of mass decn^ases, and th-it of the particles of tne nod; dissolved iu- preases, since thej begin to combine with each pther. There must consequeniiy be a momen^ 92 CHEMISTRY in whicli the aftinity of the salt overpowers that of tlie liquid ; and from this moment the salt vhich forms itself into crystals must retain a portion of it. This water of crystallization enters as a principle inlo the combination, since that liquid cannot be discovered either by the eye, or by the touch, or by hygrometrical tests. This water of crystallization contributes to give to the crystal its form, transparency, and cohesion. When it is disengaged by heat, these three characters almost always disappear. If, for example, you expose to heat a transpa- rent crystal of sulphate of lime, you will in- stantly perceive the water to become volatilized and dissipate d in vapour; the crystal will lose its transparency, and be rendered friable and pulverulent. Simple substances, such as metals, certain earths, sulphur, phosphorus, resins, and, in ge- neral, all such bodies as are simple, and not so- luble in w^ater, crystallize without retaining a sensible quantity of their dissolvent. But com- pound substances require to be dissolved in a liquid, that they may there acquire the portion necessary for the formationof their crystals. APPLIED TO THE ARTS. 93 The water of crystallization is more or less abundant in salts. Mr. Kirwan has determined the quantity in the principal sulphates, ni- trates, and muriates, in the following table. One Hundred Parts. Sulpliates of potash , • soda. . . -^ ammoniac. — magnesia, . — alumine.. . — * iron — copper — zinc Nitrates of potash . . . . « — soda " ammoniac, *— — ' ■ ' ' lime __., — . — — magnesia. . Muriates of potash ■ soda ammoniac, lime.... . ... > 31 14 42 24 24 20 30 22 30 29 46 33 36 30 33 52 42 63 22 40 63 50 40 63 50 40 W 19 18 27 ^ 27 20 6 64 IS 57 59 55 43 53 21 14 .35 37 7 17 3 20 t)4f CHEMISTRY There are salts, which;, though obtained hf evaporation, do not always present themselves with the same quantity of water of crystalliza- tion. This was long since observed to be the case with sulphate of soda, which, by the eva- por:ition of the liquid that holds it in solutior»> partly precipitates itself in a crust which is free from any water of crystallization, while the li- quid still keeps back a great quantity of salt in Solution, I have had occasion to observe this phenomenon on a large scale in the manufac- ture of copperas. When the solution of sul- phate of iron has ariived at a concentration of thirty-seven Oi tijirty-eight degrees of Baume's areometer, the liquor becomes white and tur- bid ; a white precipitate is formed, and adheres to the sides of the vessel so closely, that there is some difficulty in separating it from them, which must be done with great care to keep the boilers from melting. This deposit is nothing but sulphate of iron nearly deprived of the wa- ter of cryst tllization. As soon as this deposit is formed, the liquor resumes its greenish co- lour, a8 CHE -.ISTRY covering may be formed of charcoal^, straw, and clay, to concentrate heat in all cases in which it is raised to a high degree in the ftir- nacc. SECTION U. Gaicra! Frinciples rclathx to the CJioice and Emploijinent of Combustibles. It is not sufficient to procure good materials for the construction of furnaces, it is likewise neeessarv to make choice of a combustible suit- ed and adapted to the operation. 'Not only do the various kinds of combusti- bles, employed in mauufactvu'es, produce heat ®f diflercnt degrees of intensity, but the diver- sity of their nature requires that furnaces be roiistructed in a particular way, and used in a totally d lire rent manner. The combustibles employed to produce hc ployed. We likewise meet with a coal that is friable, often humid, and crumbles into dust b\' long contact with the air and water. Properly speaking it is but a bituminous pyrite, which cannot be employed for any other purpose than the calcination of limestone. When the production of heat is the only consideration, all these kinds of coal may be used to greater or less advantage; but in most operations performed by means of fire, it is ne- cessary to take into account the effect of the combustible, as well on the furnaces, as on the substances which are wrought on them. To judge of combustibles by the heat thev produce, there is none that deserves to be pre- APPLIED TO TUE ARTS. ?11 terred to pit-coal : but tlie sulphur whicli it contains in greater or less quantity destroys the furnaces, corrodes the boilers, and renders all metals wrought by the fors^e short and brittle. Compared with charcoal it has the further dis- advantage ofproducing smell and smoke, of not burning well except in a large mass, and of being incapable of graduation in its action with the same facility. When the only object ii» view is to obtain heat from coal, it is prepared by a carbonisa- tion nearly similar to that which charcoal un- dergoes. This carbonisation is effected in the follow- ing manner : Raise a heap of coal into the form of a pyramid ; make a chimney in the middle, and galleries below, to produce a cur- rent of air. Throw lighted coal into this chimney ; the fire extends by degrees to the whole mass. When the flame begins to escape at the sides, cover them with damp earth to stifle the combustion. Close, at the same time, all the lateral apertures, and the chimney which had served for air. When the mass is cold a light spongy matter, which is called 112 CHEMIStRV colxC, and \vliich h, in fact^ charred coal, is lefi bcliind. Coke has several advantages over coal: 1. It yields no smoke^ which renders it valuable for dwelling-houscSj and for shops where a bi- tuminous smoke might alter colours. 2. It yields a stronger, more equal, and more unin- terrupted heat. But it produces less flame than coal, which limits its uses. In short, none but coal of good quality- is susceptible of car- bonisation. Turf is employed in all countries where it can be procured at a small ex pence. This combustible, when thoroughlj' dried, gives a brisk and pretty hot flame, but it is very speedily consumed. The smell which exhales from turf, while burning, is extremely disagreeable, and this has contributed not a little to prevent its use. Some have attempted to carbonise turf, with a view to take away its smell, and render it. lighter for carriage ; others have endeavoured to reduce its bulk by a violent mechanical compression ; but all these expedients have not given to turf the qualities of other combus- APPLIED TO THE ARTS. 113 tiblesj and its use is exceedingly limited, except in the parts where it is procured. It were, however, to be wished, that the use of this fuel might become more general ; for had it no other advantage than that of producing a com- petition with other combustibles, it would be very useful to society, which sometimes suffers from the high price of coal and wood. Charcoals present still greater difference in their effects than pit-coals. That of white woods is light, not sonorous, burns with faci^ lity, gives heat, but it is liable to waste, crum- bling to dust in the warehouses, and losing in time almost all its qualities. This charcoal is employed in the manufacture of gunpowder ; and it is ascertained, that the more recently it has been made the better it is. The charcoal produced by hard woods, such as oak, box, holm-oak, &c. is very ponderous, sonorous, and breaks smooth. It burns well, wastes little, gives a strong heat, and ought to be preferred in all cases where a lively and con- stant heat is required. Bark furnishes an earthy and bad sort of charcoal ; accordingly, those who wish to have charcoal of excellent quality, take the precau- VOL. I I 114 CHEMISTRY tion to strip the wood of its bark previous io carbonisation. Charcoal made from leaves and shoots of a yearns growth is lights without -consistence, and soon consumes. The charcoal from trunks and old branches" is porous and foliated ; it crackles in the fire, and wastes itself in sparks, if the fire be stirred ever so little. Stems of three or four years, stripped of their bark, furnish the best charcoal. The manner of charring wood has also a very powerful influence on the quality of the charcoal. Wood may be inclosed in iron tubes, to which a sufficient degree of heat is applied to convert it into charcoal. This method is pre- ferable to every other for obtaining good char- coal ; but it is expensive, and can only be prac- tised for delicate operations. It is employed in some countries in order to produce an excel- lent charcoal, with which gunpowder of a very good quality may be made. Charcoal may likewise be made by burning wood in holes till the space is filled with char- coal: it is then covered with some wet substance. APPLIED TO THE ARTS. 115 on which is quickly thrown a deep layer of earth to retard the combustion. In a few days the covering is removed with care, and the charcoal taken out of the hole. This process is generally employed to prepare the charcoal which is intended for making gunpowder. The third method of charring wood is that which is universally practised in the forests. It consists in piling together a heap of wood;, more or less considerable, and contriving cur- rents which run from the circumference to th6 centre, and unite in one common chimney. This pile of wood is lighted in the middle, and when the flame begins to escape on the out- side, the whole surface is covered with earth ; the air-holes are stopped ; the combustion is thus extinguished, and the operation continu- ed by means of the heat, till the whole is con- verted into charcoal. It has been observed, and when I was at the head of the administration of salt-petre and gunpowder works, I had occasion to verify the observation, that charcoal produced from the same wood, but made in a hole, is invariably lighter, and less hard than when made in tht open air. 1% !!• CHEMISTHY ' Besides the difference of qualitj arising- from the method employed in the carbonisation, charcoal likewise varies from having been more or less recently made. Fresh made charcoal possesses properties which it loses by age : it not only effloresces^ in time^ but also imbibes water in the ])roportion of twenty and twenty- five per cent, of its weight. It has accord- ingly been observed for some years past, that to make good gunpowder^ it is of much less importance to pay attention to the qualities of the saltpetre and sulphur^ than to employ fresh charcoal w hich has undergone none of the al- terations that result from long exposure to the air. Charcoals, in general, give little flame and produce a great heat, so that they are prefer- able to wood in all the operations of fusion, in which it is necessary to apply to a body a ,strong and long-continued heat. Some woods are likewise preferable to others for producing flame and heat : hard woods .give more heat than flame, and consume slowly ; white woods are soon spent, but they give a good heat and a clear flame ; resinous woods APPLIED TO THE ARTS. 117 burn well, and give much flame^ but they emit a very troublesome smoke. In all the establishments in which a bright, strong, clear flame is required, as in glass- houses and porcelain manufactories, they take the precaution to cut the wood longitudinally, to divide it into very thin pieces, and to dry it with care. By these means it not only burns with facility, and produces a great heat, but it does not introduce into the interior of the fur- naces those currents of aqueous vapors, which, besides the natural effect of retarding the bak- ing, cause the vessels exposed to their action to break. It seems scarcely necessary to observe, that the climate, the exposure and the nature of the soil, modify the qualit}' of wood in a very re- markable manner. It is generally known that wood exposed to the south burns better than other wood of the same kind which has a northern exposure. The same difference is ob- servable ^between that which grows in a dry soil, and that which is r that these crucibles cannot be employed for fusion^ except !Q very few cases. 136 CHEMISTRY When a crucible is used in the forge, it is placed on a small round earthen stand, as large as the bottopi of the crucible, and very refrac- tory. The stand raises the crucible, so that the bottom of it is on a level with the apertures by which the wind of the bellows is discharged. When the substance that is to be melted is put into the crucible, it is covered with a lid made ef the same material, to prevent coal from fall- ing into it. When the matter is melted, and you design to run it into ingot or other moulds, you lay hold of it with a pair of crooked tongs, which embrace its whole circumference, and prevent the possibility of any accident. Plate I. The crucibles which are employed in glassr houses are composed of raw clay, mixed in due proportions with baked clay, proceeding from broken pieces of old pots. In this instance quartzose sand cannot be employed, because, as alkalis form the base of the composition of glass, they would dissolve the quartzose portion of the crucibles, and accelerate their destruc- tion. On the composition of these crucibles, in particular, the utmost care should be be- stowed; for being incessantly exposed to th^ APPLIED TO THE ARTS. 137 consuming action of a very powerful fire, and to the effort of the enormous mass of mf^tter ■which thej contain, thej ought to oppose an equal resistance at every point, so as not to suffer the fire or the matter in fusion to make more impression on one than on another. The reader will be much more sensible of the im- portance of bestowing particular care on the selection of materials, and on the fabrication of pots for glass-houses, when he considers, that the necessity of replacing these crucibles, which are very expensive, is attended with a suspension of business, or, at least, occasions considerable derangement. Jn the operations performed on ores for the purpose of extracting the metal by fusion, they generally employ large bellows made of v/ood, and with a single bottom, so that, to obtain a constant current of air, it is necessary to place two of these instruments beside each other, and to make them act alternately. They are almost always worked by means of the axle of a wheel moved by w ater. The use of trunks has been introduced for a variety of purposes, and the effect which I have seen them produce has convinced me that not IBS CHEMISTRY only the air Ihey discharo;?. raises a greater heat, but that their action is infinitely superior to that of the strongest bellows, I shall here s:ivc the fiffure and dimensions of the trunk which produces the best effect of any I have yet seen. Plate 11. figs. 1 and 2. Take a cask ddcld, four itot six inches wide, four feet eight inches high, with the bottom knocked out, and plunge the lower part into water to the height of seven inches and a half. In the middle of this cask is placed a stone, c, rounded off at the top, standing in the water, and rising about eleven inches above the sur- -face of the liquid. In Ihe upper end of the cask is made a hole, to which is adapted a leathern pipe, intended to convey the air to the fire-place, which is to be supplied with it. jFrom the top of the cask rises a hoUow^ cylin- der, eighteen feet in height, and eighteen inches wide within. This cylinder grows narrower towards the top, and opens externally by four apertures about five inches wide, situated on the four sides of the cylinder cc. On the top of this cylinder is a hollow cone, the base of which forms one of the sides of the APPLIED TO THE ARTS. 139 apertures. This cone is six feet in lieiglit, the opening at the upper end is eighteen inches wide, and that at the lower end five inches. This brief description will suffice to give an idea of the action of the trunk. A current of water is brought from above the funnel which crowns the trunk ; the current rushes into the tree of the trunks and is broken by the stone placed in the middle of the cask ; the air which is disengaged from it being unable to ascend again, on account of the continual fall of the water, is obliged to escape by the latei"al open- ing, g, which conveys it to the fire-place. In some of these machines the trunk is made without holes, so as to form merely a hollow cylinder, surmounted by an inverted funnel, and supported by the cask ; but I am far from considering these apertures as useless. I have constantly observed, that when the water pre- cipitates itself into the tree, a rapid current of air rushes through them with such impetuosity, that a handkerchief held near them is forcibly carried into the inside. Thus the air of trunks proceeds not only from that which is in the water, but likewise from the current formed by the apertures. 140 CHEMISTRY I made an experiment, which demonstrates, that the most quiet water contains a verj con- siderable quantity of air, which may be disen- gaged by the mere shaking or the fall of that liquid. For this purpose, it is sufficient to place a metal tube at the bottom of a tub full of yrater, and to pour it into a cask placed under the tube, and disposed as in the ordinary trunks, By this method a prodigious quantity of air is disengaged; but what is truly surprising, is, that if the water be repeatedly put back into the tub, and poured off again in tiie same man- ner, it still continues to furnish a very consi^ derable quantity of air. In large establishments, \\here they have oc- casion to melt considerable quantities of matter at once, furnaces are constructed with bricks, or at least their interior is lined with them, Thece bricks should be perfectly refractory ; and on this subject we could only repeat what we have already said concerning furnaces and crucibles, were we to enter into any details on the care which it is necessary i^ bestow on the selec- tion of the materials employed in their com- position. *• The form of wind-furnaces of fusion varies APPLIED TO THE ARTS. 141 according to the nature of the mineral that is %vrought in them. It would lead us into a discus- sion much too prolix were we to attempt a de- scription of them all. We shall therefore con- tent ourselves with giving, in this place, the figure of that which is most generally employ- ed in the smelting of iron ore. Plate II. figs, 3 and 4. In all furnaces the mineral is thrown upon the fuel, which forms a thick mass, so that in passing through it becomes heated, is reduced, and in a state of fusion before it reaches the bason, where it receives the most violent blast, and where the matter is refined by heat and rest. ARTICLE n. Furnace iiith a free Current of Air. The heat of a furnace is the stronger the more rapid is the draught; and this essentially depends on the proportions that are given to the different parts composing the furnace. 142 CHEMISTRY In all furnaces with a free current of air » careful distinction must be made between the ash-pit, the fire-place, and the chimney. In most there is a fourth part, called the^oor, or the laboratory. This, in all of them, is a space between the fire-place and the chimney, where the metal intended to be melted is put. The floor is subdivided into two parts, which the French distinguish by the appellations of autcl, or the altar, and creuset, the crucible. The first is next to the fire-place ; there the metal to be melted is deposited. The second is the opposite part, next to the base of the chim- ney, and receives the metal as it runs oft'. The n^li-pit should be wide, deep, and pro- tected from too rapid currents of external air. It is separated from the fire-place by a grate which supports the fuel, the bars of which should be at such a distance that the coal can- not fall through, but nevertheless not so close as to interrupt the passage of the air. To judge of the draught of the furnace, and to prevent the grate from being choked, you m^y place a basin full of water on the bottom of the ash- pit; the vivid light of the grate reflected in it shews, every moment, what points are choked APPLIED TO THE ARTS. 143 on which you restore the draught by removing with an iron poker the matters which obstruct- ed it^ and by raking out the scoria. We shall content ourselves with giving^ in this placC;, a representation of three furnaces of fusion with a free current, which produce thfe most powerful effect, and which are most com- monly employed in operations. The first (Plate III. fig. 1.) is the melting furnacd of our laboratories, improved by La- voisier ; it stands on a trevet, and draws in the air with its whole bottom, which is open. It is used with the greatest success for melting in crucibles. It is reduced in the engraving to one-twelfth of its actual dimensions. The second (Plate \1\. Jig.%.) is a furnace, very commonly employed for melting metals in the laboratories of mints. In these two furnaces no distinction is made between the fire-place and laboratory ; the cru- cible is set in the fire-place, and covered with coal. But we have already observed that there are furnaces, in which the floor or laboratory is si- tuated between the fire-place and the chim- ney. In these the flame^ wliich rises from the 144 CHEMISTRY fire-placcj strikes against the arch over the flooFj and is thrown hack with violence on the spot where the matter to be melted is put. This has occasioned these furnaces to be called re- verheratorij furnaces. They are used for smelt- ing metals. (See Platclll.Jig. 3.) Thej are likewise cmplojed for calcining or oxydizing metallic substances^, and often for extracting the most fusible metals^ as lead, from their ores. In this latter case it is necessary to mix wood- charcoal with the ore^ as well to reduce the metal, as to prevent its ulterior oxydation. The slightest inspection of the structure of the two first mentioned furnaces with a free current will satisfy the spectator that wood cannot be employed in them for fuel ; but the case is different with respect to the third. In this the effect is produced at a certain distance from the fire-place ; it is entirely owing to the flame; and under this circumstance dry wood is productive of the best effects. W hen the furnace is heated with coal, it is sometimes thrown in through a perpendicular aperture made in the arch ^^hich covers the fire-place. It is more frequently introduced by lateral apertures, that are nearly level with APPLIED TO THE ARTS. 145 the grate, and these apertures are filled up with coal, so that nothing more is necessary than to push it into the fire-place whenever occasion requires. The only modification that is made in the reverberatory furnace, when it is heated with wood, is to lower the grate ; because the fiame, which is stronger, would then pass over the floor, and be partly lost in the chimney. SECTION VI. Application of the preceding Principles to Fur- naces of Evaporation. Evaporation signifies the conversion of a li- quid into vapours by means of caloric. The object of this operation is either to se- parate matters from each other, one of which at least is liquid, and which possess a very different degree of volatility : or to concentrate a solution by the subtraction of a portion of the liquid, in order to obtain separately the substance which is in the liquid, VOL. I. L 146 CHEMISTRY Evaporation is performed in furnaces^ wliicll, from their use, are called ei'aporating fur- naces. The evaporating furnace is generally com- posed of isvo distinct parts, the a.^.h-plt, and the fire-place. They are separated by a grate ■which supports the fuel; each of these parts has an aperture, one of which affords a passage for the air, and for taking out the ashes, while the other facilitates the use of the fuel. In the furnaces in which wood is used there is no ash- pit; and in this case, the current of air is formed by the door of the fire-place, where care is taken to keep lighted coal or wood, that the fresh air may not rush against the eva- porating vessels and moderate the heat. The simplest of all evaporating furnaces is that of our laboratories ; it is shaped like a portion of a cylinder open above ; at the top three or four holes are made in the wall to af- ford a passage to the current of air, which, af- ter animating the combustible, must escape from the furnace. Plate W. fig. 1. A great variety may be observed in the eva- porating furnaces that are in use. The form of the vessels employed for evaporation, and APPLIED TO THE ARTS. 147 the nature of the substance evaporated^ must necessarily occasion many modifications in * their construction ; we shall confine ourselves to a description of the principal ones. The boilerS;, or pans^ used in manufactories^ may be considered as the most common evapor- ating vessels. They are employed to concentrate and thicken liquids^ or to separate the salts or other substances which may be contained in them.. The form usually given them is an ob- long square;, but sometimes it is circular. Before the construction of furnaces received the improvements that have been of late years made on them^ boilers were merely fixed on four wallsy in such a manner that the fire-place oc- cupied the whole length and breadth^ except about three or four inches on each side, where the boiler rested upon the walls. A door made in the middle of one of the walls facilitated the use of the fuel, and afforded a passage for the air ; the chimney was constructed at the op- posite side. From the idea we have given of the bad construction of our ancient furnaces^, it is ob~ vious that the current of air established be- tween the boiler and the bottom of the fire- 148 CHEMISTRY place carried away the heat, and threw almost all of it into the chimney ; so that it required a great length of time, and a prodigious quan- tity of fuel to produce an evaporation. The progress of science, and the necessity of saving both time and fuel, could not fail to in- troduce changes in the construction of the fur- naces, of which we are about to treat. The construction of a furnace cannot be pro- nounced good, unless the heat be equally ap- plied to every point of the surface of the eva- porating vessel, and unless all the heat pro- duced by the combustion be advantageously employed. It may therefore be asserted, that there exist imperfections : 1, Whenever only one of the surfaces re- ceives heat, because the general mass of the liquid is heated only in proportion to the trans- mission of the heat by that part of the furnace, and of the liquid which immediately receive* it: so that the operation is prolonged. 2. Whenever the chimney is seen to smoke ; for this smoke, composed entirely of combusti- ble bodies carried away by the current of air. APPLIED TO THE ARTS. 149 announces that tliej have escaped the combus- tion. 3. Whenever a strong impression of heat is felt in the current of air which passes a\Yay through the chimney. By making some changes in each of the parts belonging to an evaporating furnace;, it has been at length brought very near to per- fection. When coal is employed, and an ash-pit is consequently necessary, care is taken to make it deep, both to prevent the small lighted coals which fall, and the heat of the grate from vrarming the contiguous air, and to protect it from the currents of external air, which inces- santly varying in force and direction, render the combustion unequal. The fire-place and the chimney require par- ticular attention. The grate should occupy two-thirds of the length, and one-third of the breadth of an oblons: boiler ; it ought to be placed about three inches below the stone on which the door rests, so that there may be a slope in the thickness of the wall against which the grate is supported. The grate should be formed of iron bars laid without fastening, on 150 CHEMISTRY stands of the same metal, placed across, and about an inch distant from each other. Iron bars, which are fixed or fastened, are liable to twist and warp from the change of dimensions which thej undergo in passing successively from cold to heat, and from heat to cold. The boiler should be placed ten or fifteen inches above the grate; the nature of the fuel prin- cipally regulates the height, according as it gives more or less flame, or burns with greater or less activity. The heat arising from a fire-place exercises its maximum of action at a height which it is necessary to ascertain, but which varies from the causes we have just mentioned. In general the combustible which yields much flame re- quires a greater height; that which burns with violence, and leaves but little residue, requires a less height. Between these two extremes a suitable elevation ought always to be taken. When a round boiler is to be placed on a furnace, it is necessary to make certain modifi- cations in the construction of the latter, espe- cially as far as regards the position of the grate. In almost all manufactories the boiler is placed in such a manner that the centre of its bottom APPLIED TO THE ARTS, 151 corresponds with the ceiitie of the grate. This disposition would be better if the heat of the iire-plaee rose perpeadicularlj to strike ag-aiiist the boiler; but the current of air which car- ries avvaj the flame in its passage to the chim- ney, gives it an oblique direction ; so that the current of heat strikes only that part of the boiler which is nearest to the chimney. To ob- viate this inconvenience^ it is suOicient to place the grate more forward^ so that the end next to the chimney may correspond with the middle ofthe boiler^ and that the door of the fire-place may be perpendicular with the front, as is re- presented iaplalcY.Jlg. 1. In this position, the flame wbich rises from the fire-place ru::;hes with violence a2:ainst the whole surface of the bot- torn of the boiler before it is lost in the chimney. But it is principally in the direction of flues that the most advantageous alterations have recently been made, instead of being raised perpendicularly from the fire-place, they are made to turn round the side ofthe boilers be- fore they come to the perpei^idicular chimnej', which immediately communicates with the air : so tl. at the portion of the heat which escapes from the fire-place is applied to the lateral sur- 153 CHEMISTRY faces of the boilers on which it^ exerts its in- fluence. At the further end of the fire-place^ opposite the door^ are sometimes made tv.o apertures^ which form the commencement of spiral flues, and which unite, over the door of the fire- placCj in a single flue, by which the current of air, which has served to animate the fire, es- capes into the atmosphere. ( See plaie \ .fig. 2. ) In this case the perpendicular chimney is over the door of the fire-place. In general, however, the current issues from the fire-place only by an aperture. The spiral flue then terminates in the perpendicular chim- ney, on the side opposite to the fire-place and ash-pit. See plate Y .fig. 3. \Vhen the boilers are very large, and it is diSciilt to heat their base without employing a prodigious quantity of fuel, other spiral flues are made to open into those which run all round. See plate Y.fig. 4. This last construction possesses the advantage of supporting the boilers, aiid preventing them from protruding, an inconvenience to which boilers of lead and copper are particularly APPLIED TO THE ARTS. 153 liable, and which occasion their specdj de- struction. The walls which separate the winding Hues of the chimney below the boiler should not be more than a brick in thickness. At the moment of setting theboiler;, the up- per surface of these partitions should be cover- ed with a coat of luting, made of horse-dung and argil kneaded together, that the boiler may touch at every point, and that the flame^ or current of air, which issues from the fire-place, may be obliged to pass through the whole ex- tent of the chimney. The furnace of which we are now speaking is attended with very great advantage when wood is used for fuel, because the flame which it produces penetrates the sinuosities of the chimney throughout almost their whole ex- tent, and because the heat is applied to ail the surfaces of the boiler. Notwithstanding the advantages of the spiral chimney in furnaces, there are cases in which it would be dangerous to employ it. In soap- boiling, for instance, the soap would not only be burned by heating the sides of the boiler in their whole height, but it would produce a 154 CHEMISTRY swelling of tke liquid^ which it would he ex- tremely diilicult to correct. Accordingly, only the bottom of the boilers used by soap-makers are constructed of copper, the rest being com- posed of freestone firiijly joined together. Another difference exhibited by boilers in- tended for soap, is, that the grate, instead of being in front, near the do(?r of the fire-place, is situated at the back part of the bottom of the boiler ; so that the flame of the combusti- ble proceeds directly toward the door of the fire-place to gain the chimney by passing un- derneath the boiler; which is clearly a con- trary direction to that which it follov. s in other furnaces (See Plate VI. Jig. 1.). This curious form of construction has been adopted, because it has been observed, that, by this method, the action of the heat is more equally distributed than in the other furnaces. \1 e now come to treat of evaporating ves- sels, which, as we have observed, are the ves- sels that contain the liquids to be evaporated. Evaporating vessels are of metal, glass, por- celain, or stone ware. They are denominated boilers^, pans, and capsules, according to their dimensions APPLIED TO THE ARTS- 155 A boiler is solidly fixed in a furnace ; it is of a square, round, or oblong form ; of copper, iron, tin, or lea^, according to the nature of the substances for which it is intended. Those of copper are employed in dyeing, and generally in all operations performed on vegetables, for the purpose of extracting certain principles. Those of iron are used in manufactories in which the saline principle is extracted, or in which dissolutions of neutral salts are concen- trated. Those of lead, less assailable than the latter by saline dissolutions, are used in alum, copperas, oil of vitriol works, &c. I know of but one purpose to which tin boilers are ap- plied, namely, in dyeing, to dilute the comjposi- tion, or the mordant of scarlet, because that acid liquor attacks the other metals more or less, and the colour is tarnished and injured hy them. The form of boilers lias always appeared to me to bean object of little io^portance, if the furnaces were but well constructed. It is, ne- vertheless, true, that those of a circular form are more easily heated than the others, and that they are less liable to injurj. I should therefore prefer them for the purposes of eva- 155 CHEMISTRY poration ofiI v ; liiit v/ben it is necessarv ^o work by flipping into the boiler, the raanipulations are rendtred more easy by the sqii:*ie form : conse- quently the nature of the operations must de- cide with respect to the form to be adopted. The flat bottom of round boilers has always appeared to me to be attended witli inconve- niencies. 1. It is difficult to empty the bot- tom of a boiler which has this form ; 2. The im- purities which often sully the contents^ and are deposited over a lar2:e surface^, remain exposed to the tumultuous action of the liquid; 3. The liquid bears every where with its whole weight on the bottom already weakened by the heat. By making the bottom of boilers to project inwards, so as to present a concave surface ex- ternally^ all these defects may be corrected^ and other advantages procured. J. The fire is ap- plied in a more equal manner to every point, from this circumstance alone, that the greatest heat rises in the middle. 2. This internally con- vex form opposes more resistance to the efforts of the liquid and the action of the heat. 5. The deposits formed in the bath are throw n to the sides of the boiler which rest on the brick- work, where the fire is less active, and conse- APPLIED TO THE ARTS. Ic7 quently where there is less danger of their forming a crust, and interposing between the liquid and the metal, which very often occa- sions the melting of the boiler. See Plate Vl. jig. 2. It has long been a subject of dispute what proportions are the most advantageous to be given to a boiler. From the experiments with which we are acquainted, we may now deduce the following consequences : the quantity of fuel necessary for evaporation augments only the volume of the liquid in the same propor- tion, so that there is an advantage in employing large boilers : but more time is required to bring the latter to ebullition ; and as time is an element of calculation in the interest of the manufacturer, it depends on himself to deter- mine the dimensions of his boilers. Count Rumford kept boiling, at different times, for an hour, four hundred and forty and two hundred and eighty pounds of water. In the first instance eighteen pounds of water were kept boiling by one pound of fuel, and in the second only twelve pounds. It may be adapted as a principle, according to Count Rumford, that the savins: of fuel i^ 158 CHEMISTRY greater in proportion to the leiigtli of time ne- cessary for producing ebullition. The pans employed in the sliops of the con- fectioner and apothecary to concentrate juices, to make decoctionS;, &c. are small, portable boilers, which are placed on the fire-place of a furnace, or merely on a trevet, under which wood is burned. They are of copper or of silver. The latter should be employed in all cases for the concentration of juices or salts in- tended for medicinal purposes ; because cop- per is liable to be corroded and dissolved, and that metal would impart very pernicious quali- ties to medicines. But as, in our domestic eco- nomy, we may not have silver pans at our dis- posal for the preparation of extracts for food, we ought at least to be extremely cautious in the use of copper. It should be rubbed with care to remove the rust or verdigrease which is so easily formed on the sides. In the south of France, where they prepare great quantities of the extract of grapes, called raisine, they cor- rect, in part, the inconvenience of the copper pans in which this preparation is made, by leav- ing in them, during the whole operation, iron keys, which, when taken out, are redj and in- APPLIED TO THE ARTS. 1j9 crusted with copper. In this instance the iron precipitates the copper as fast as it is dissolved, and takes its place. The motion given to the liquid to forward the evaporation, and the fric- tion exercised with wooden spatulas on the sides of the vase to prevent the substance which is thickening' from adhering to them and burn- ing, facilitate the corrosion and the dissolution of the copper. The capsules, or evaporating vessels employ ed in our laboratories, have, in general, the form of segments of a sphere, and are made of glass, porcelain, or metal. Glass capsules are in most general use ; but those made in glass-houses have various de- fects: 1. They are almost always of unequal thickness in different points^ v.bich, prevent- ing a uniform dilatation by heat, renders them liable to break. 2. They present two or three prominent points in the convex part, which proceed from this circumstance, that the work- man, in order to polish the edges, is obliged to lay hold of them on thett side ; but these points are frequently the occasion of the fracture of the vessels. The best capsules are such as you mav vour- 160 CHEMISTRY self prepare by cutting a glass receiver into two semicircular vessels. This process may be performed in different ways: 1. You may tie a piece of packthread round the receiver at the place where you in- tend to cut it. Fasten the cord with a lute made of argil and horse-dung kneaded toge- hich would empty itself into the second, the second into the first, and the first into the receiver. This inconvenience in Woulf's apparaius has been obviated by M. Melther's contrivance of tubes of safety xxxx : for it is evident that th€ external air must ruhh ihroui^h these tube?, and soon restore the equl- 176 CHEMISTRY librium, whenever the smallest vacuum begins to take place in the vessels. As the tubes are plun;L,e(l into the liquid in the bottles, and those which are fastened to the curvatures have ;some water in the ball qg, it is impossible for the va- pours, which are disengaged by distillation^ to escape iuto the air. The operation of distilling may be perform- ed in the same apparatus on a sand-bath, as represented in Plate VIII. j^g. 2. The apparatus described above is one of the greatest improvements that could have been introduced in our laboratories. It not only af- fords us a medium of collecting all the products of a distillation, but also enables us to obtain them separately ; it removes all fear of any ex- plosion in a laboratory, and prevents the vola- tilisation of any acrid, pungent, or dangerous substance, which alike incommode the artist. This apparatus is now known in our large manufactories ; it is used for the preparation of muriatic acid, ammonia, &c. Distillation is one of the operations most frequently performed in chemical laboratories. It is employed to separate the constituent prin- ciples of a body, almost always susceptible of APPLIED TO THE ARTS. 177 Volatilisation at different degrees of heat ; and to collect the gaseous substances, which are de- tached from their combinations by re-agents possessing a stronger affinity for their base. The analysis of vegetable and animal matters by the retort furnishes us with an application of the first case : the decomposition of muriate of ammonia with lime, or muriate of soda with sulphuric acid, affords an example of the se- cond. We shall make a few observations on the distillation of plants, in order to present an application of the principles which we have laid down. The distillation of plants was almost the only method of vegetable analysis practised before the middle of the last century. But the uni- formity of thje products obtained from almost all vegetables might have sufficed to produce a conviction that this method was defective. Caloric, which enters as a principle into distil- lation, gives a new form, and imparts a pecu- liar character to the substances with which it combines. As it first separates the most elastic principles it destroys ithe nature of the com- pounds to which they belonged ; it forms new combinations by detaching and bringing into TOL. I, N 178 CHEMISTRY action matters possessing the same degree of volatility^ and \vhich escape at the same time ; so that it produces water, acids, and ammonia, which did not exist in the vegetable. In a word, the products of the distillation of a plant no longer exhibit the nature and organic state of the vegetable, any more than the ruins of a conflagration represent the design after which the consumed structure was erected. In cither case vou find nothino- but the disor- •J o der of decomposition, and a mixture of some primitive principles preserved in their original nature, with many others which have been al- tered, and with various substances of new formation. But these products, whether se- condary or primitive, afford qualities of which human ingenuity has availed itself; and it is this that renders distillation a highly interesting operation for the arts. It is by its means that we extract volatile oils^ the odoriferous princi- ple, or aroma, distilled waters, pyroligneous acid, hydrogen gas, &c. But, as most of these operations are perform- ed on a large scale, and as some form distinct arts in society, such as those of the perfumer and distiller, larger vessels than retorts are em- APPLIED TO THE ARTS, IJ9 ployed, and alembics, of which we now pro- ceed to treat, are made use of in their stead. ARTICLE II. Distillation with the Alembic. The aleivMc is a kind of metal retort, to the heck of which is adapted a long, spiral tube, fixed in a tub full of water to produce the con- densation of the vapours. Though the alembic is employed to extract the odorous principle of various substances, ais well as tlie volatile oils of plants, yet we shall apply the principles of distillation to that of win€s, which is, doubtless, the most interest- ing of any. The amendments which we pro- pose in this apparatus for distillation, may be applied to all the purposes for which the alem- bic can possibly be employed. The alembics that were used at the remote period, when the distillation of wines first be- J2:an to be practised, were boilers with a long, N 2 ISO fHEMISTRr cjliiidrical neck, narrow, and fitted into a hop- low hemisphere, from which a tube of no great width convejed the liquid into the "Worm. Arnauld de Villeneuve seems to have been the first person in France that gave his country- men precise notions relative to the distillation of wines ; and to him they were indebted for the first description of that kind of alembic w ith a very long neck, patterns of which may still be found in the shops of perfumers. The idea that the produce of the distillation was the finer^ purer, and more subtle, the higher it was raised by causing it to pass through narrow tubes, led to the construction of these vessels for distilling ; but it was not long before alterations were made in the ap- paratus. It was imagined, that the art of gra- duating the fire, rather than the obstacles op- posed to the ascension of the vapours, rendered the produce of the distillation more or less pure. But at the period i»\hen chemistry began to survey the operations of the arts with more judicious eye, it was thought that still more \ APPLIED TO THE ARTS. 181 advantageous alterations might be made in tlai^s distilling apparatus. The form of the boiler was judged too high and not sufficiently wide ; for as the fire acts only on its base, the distillation proceeds slowly ; and the deposit, formed during the evaporation, receiving a too violent degree of heat, contracts a disagreeable taste of fire which is communicated to the spirit. The contraction of the upper part of the boiler seemed to oppose the free ascent of the yapours. It was thought, that as this part of the boiler was not covered with brick-work, and was exposed to the atmospheric air, the temperature must be cooler there than in the other points, and consequently the portion of the column of vapour which touched the sides must become cooled, condensed, and fall back into the boiler. It was imagined, that this un- covered part of the boiler might be compared to the portion of the retort, which, in distilla- tion by the sand-bath, is not covered ,vith sand ; and as it is observed that, in this case, the liquid which rises in vapours is partly con- densed, and running in drops down tb - ' especially in the north of France, were so ac« customed to it, that for some time they refused to drink the milder and more pleasant tasted spirits, so that the distillers were obliged to rendei' them empjreumatic by the admixture of burnt spirits, in order to suite their taste. Wines furnish more or less spirit, according to their degree of spirituosity : a Tery generous wine yields one-third of its weight of spirit. In Languedoc the average produce is one- fourth; the wines of Bourdeaux yield one-fifth^ and those of Burgundy not so much. The spirit extracted from old is of better quality than that obtained from new wines. Saccharine wines furnish an excellect spirit. Sour wines yield a spirit of \evy bad quality, on account of the great quantity of malic acid, which is almost inseparable from them. By diluting the husks of pressed grapes with water, and proceeding to distillation, you o2 196 CHEMISTRT obtain a further portion of spirit, but it is 02 bad quality. In distilling for the purpose of extracting spiritS;, you continue the operation till no more spirit of wine passes over, or till the produce ceases to be inflammable. The distiller forms a judgement of the degree of spirituosity of the liquor which is distilling, by the number and size of the bubbles produced by agitating the liquor, and by the longer or shorter time of their duration. For this pur- pose, he either pours it from one glass into ano- ther, letting it fall from a considerable height, or he fills a long bottle two-thirds full, and stopping it with his thumb, he shakes and strikes it with force against the hollow of his hand to form bubbles. Various methods for determining the strength of spirits have been successively tried and prac- tised. The regulation made in France in 1729 di- rected that some gunpowder should be put into a spoon, that it should be covered with the spirit intended to be proved, and then set fire to A judgment was formed of the strength of the spirit according as the flame burned or did APPLIED TO THE ARTS. 197 ?5rOt burn the gunpowder; but the same spirit iaflames or does not inflame, according to th§ proportion in which it is used ; a small quan- tity always takes fire, a great quantity never does, because the water retained by the residue of the combustion, is sufficient to v. et the pow- der and to preserve it from inflammation. Carbonate of potash has also been employed^, as dissolving with more or less facility, accord- ing to the quantity of water ^contained in the spirit. The Spanish government in 1?70 prescribed the use of oil for proving spirits- The process consists in letting fall a drop of the oil into the spirit; a judgment is formed of its degree of spirituosity from t|ie greater or less depth to which the drop of oil descends in the liquor. In 17T2 Messrs. Poujet and Borie of Cette turned their attention to this subject, and ob- tained results which have furnished commerce with a spirit-gage of such accuracy, as not to produce the least error in the estimates which are daily made with it. After having made very nice experiments on the proportions of water and alcohol^ and on the action of the temperature on the mixturCj 198 CHEMISTRY at every possible degree, they adapted the ther- mometer to the spirit-gage, and transferred to a scale the comparative progress of the real spirituosity, together with the effects of the temperature, so that their spirit-gage itself in^ dicates the alterations made by the tempera- ture. This instrument is now the only one em- ployed in commerce in the south of France. The use of such an instrument is so neces- sary in commerce, that for more than fifteen years I have seen the dealers of the south pur- chase Spanish spirits, which varied in the de- gree of spirituosity, and take no further trouble than to raise or reduce them to the degree of commerce, merely by adding either spirit of wine or water, in order to obtain an advanta- geous sale. ^ The produce of the distillation of wine is called in France Hollands proof spirifs. But if you again subject this spirit to distil- lationyou then obtain a more spiritous liquor, which is called tlrree-fifths. In this case three parts of the liquor, mixed with two parts of pure water, form five parts of spirits, Hollands proof. ■ With the spirit-gage of Messrs. Borie and APPLIED TO THE ARTS. 199 Poujet the different degrees of spirituosity are %^ery easily ascertained by means of silver weights of various sizes : the heaviest is in- scribed with the words, Hollands proof, and the lightest three-sevenths. The other weights serve to mark the intermediate degrees between these two terms. Thus if you screw to the end of the beam of the spirit-gage the weight de- noting Hollands proof, and plunge it into tliree-jiftlis, the instrument will descend in the liquid below the degree marked on the scale Hollands proof, but it returns to that point on the addition of two-fifths of water; so that ihreefifths spirit is thus transformed into Hollands proof spirit. If;, on the contrary, you screw on the three- fifths weight, and plunge the spirit-gage into Hollands proof , it will rise in the liquor above the latter mark, and it may be easily carried down to that degree by the addition of alcohol^ or spirit of wine. When spirits are distilled for the purpose of extracting alcohol, or spirit of wine, the bal- neum marice is generally employed. The heat is then more gentle and more equal, and the 200 CHEMISTRY produce of the distillation of superior qua- lity. Alcohol^ or spirit of wine^ is used as a be- verage. It is the dissolvent of resins^ and consti- tutes the basis of drying varnishes. Sjiiritof wine serves as a vehicle for the aro- matic principle of plants, and is then called spirit of this or that plant. The apothecary likewise employs spirit of wine to dissolve resinous medicines. These dissolutions are denominated tinctures. It forms the base of almost all the different sorts of beverage called liqueurs. It is sweet- ened with sugar, or rendered aromatic w ith all kinds of substances of an agreeable taste or smell. Spirit of wine preserves vegetable and ani- mal substances from fermentation or putrefac- tion. To this end it is used for preserving fruits, vegetables, and almost all the objects and preparations relating to the natural his- tory of animals. All the liquors produced by the fermentation of saccharine substances, yield alcohol. But the quantity and quality vary according to the pature of the substances. APPLIED TO THE ARTS. v^Ol Spirit distilled from cyder has a very disa- greeable taste, on account of the abundance of mucilage vvhich it contains ; but if great care be taken in the distillation, an excellent spirit may be obtained. The spirit extracted from cherry wine is de- nominated kirschenwasser (cherry water) that made from syrups of sugar or molasses, is call- ed rum. Pallas has seen fermented malt liquor dis- tilled near Pinbirsk, for the purpose of extract- ing spirit. To this end the people there use alembics with heads made of wood, and necks which communicate with a pipe constantly kept cool with cold water. The same naturalist relates, that the Cal- mucks leave cows' and mares' milk to become sour in vessels of leather or other substances. They assist the acetification with heat, and with a leaven made of coarse flour and salt, or with the rennet of lamb's stomachs. They do not skim ilie milk which is intended to furnish spirit. They distil the milk when quite, sour in boilers covered with a wooden head, and collect the produce in vessels which they '202 CHEMISTRY keep cool by putting them into snow or very cold water. ' Spirits are distilled from corn in almost every region of the globe^ but they are bad, and to disguise the disagreeable taste, they are distilled ■with juniper berries. These are known by the name of geneva, or gin. SECTION VIII. EesuUs of the Action of Heat, applied at dif^ ferent Degrees to zwious Mineral Sub-^ stances. Men, in all ages, have been sensible of the importance of ascertaining the effect of heat at different, and accurately determined degrees on all bodies ; and we find in almost every work the results of numerous experiments made on this subject. But not possessing the means of having a constant, equal, and very elevated heat, and besides the system of analysis not be- APPLIED TO THE ARTS. 203 ing sujOTiciently advanced to permit the chemist to operate on pure matters, or such as were constant!}' of the same nature ; the facts which have been handed down to us are not fit ob- jects of comparison, so that they are rendered totally useless to science. It is of little importance to know that a stone found in the Alps or Pyrenees is fusible or not fusible. But it is essentially interesting to as- certain by accurate experiments, 1. The manner in which every pure earth and every metal is effected by a known degree of heat. 2. The action or effect of the same degree of heat on simple substances, when they are mix- ed together in known proportions. 3. The effect of fluxes on the same sub- stances. When results of this nature are well authen- ticated they are serviceable at all times, and in all places, and the arts may rely upon them as positive facts. I conceived that it v, ould be useful to collect into a table the principal experiments on fusion, which present the above-mentioned characters. •ir t04i CHEMISTRY To this end I have selected from an infinite number of experiments^, such of the results as are capable of instructing and guiding- artists in the operations which have for their object the action of fire on bodies that are best known and most employed. Darcet was one of the first chemists that es- sayed the action of an equals long-continued, and comparable heat on a great UMmber of bodies. His experiments were made in 1766 and 17()8^ in porcelain furnaces, in which the heat was maintained at the same degree of in- tensity for several days. Lavoisier and Ehrmann essayed almost all known bodies with the blow-pipe, jind with a, current of oxygen gas. M. deSaussure made numerous experiments with the flame of the simple blow-pipe. Macqucr subjected a great number of mi- neral substances to the action of the burning glass. Messrs. Guyton, Morveau, and Kirwan have likewise employed determinate degrees of heat to ascertain the fusibility of various simple and compound substances, APPLIED TO THE ARTS. t05 From the works of these distinguished na- tural philosophers we have extracted the re- sults that compose the annexed table. From an inspection of this table, it will easily be perceived that the results of the experiments made bj different chemists do not always cor- respond. The reason of this is, that the sub- stances employed vi'ere not always exactly of the same nature, or that the crucibles or stands reacted upon them. Bat as mixtures are, in general, more fusible than pure matters, we cannot but conclude that vre have not operated on a simple substance whenever we obtain the fusion of a body, which other experiments in- dicate to be absolutely infusible. This table may still be thought very imper- fect ; but as my only object was to shev/ the action of fire on the mineral substances most generally employed in the arts, and t!ie most extensively diffused in nature, I thought fit to confine the tables within those limits. 206 ciie:v;istrv ARTICLE I. TaUe of the Action of Heat onvmious simple Mi- neral Substances. O V S5 o s '' Infusible. It Infusible. It becomes vitrifi-jdissolves the ey- ed in the parts anite on which 5 < Porcelain fire. Blow-pipe and atmospheric air. which are in contact with the crucible. M. Darcet, who first em- ployed the earth precipitated from the mo- ther-water of ni- tre, which is on- ly a mixture of lime andmagne- sia,observedthat it melted on the edges. But when he employed the earth precipi- tated from the pure sulphate of magnesia, he found it to be .infusible. ■ Rock crvstal M. de S'ussure becomes fr;?.ble,i"i'^lte.ock crystal hough slowly heated, cracks, and shivers into pieces, without any appearance of fusion. Blow-pipe and oxygen gas. Infusible. M. Guyton observ- ed that some particles united on the edges in- to a white, o- paque enamel in a spoon of pla- tina. Contracts, har- dens without melting, be- comes gritty be- tween the teeth. {Lavoisier, Guy^ ton.) Ehrmann, who asserts that he converted it into glass, did not o- perate on pure earthi Neither La« voisiernor Guy- ton obtained fu- sion. Geyer per- ceived indic.- 'tions of fusion on the angles. Ehrmann as- serts that he melted it with a remarkable bub- blmg. APPLIED TO THE ARTS. 20t B 2 a in Porcelain fire. ^ ^ White argil, well washed, ap- peared infusible to M. Darcet, as did also earth of alum well wash- ed. ^ Blow-pipe and atmospheric air. Burniag-glass, It remains at first of a pale white, emitting a blueish light ; then forms a clotted, translu- cent, and rather shining mass, surmounted with pedunculated globules. {Dt First forms a spongy mass then a gre)^ then a snowy white, then transparent buttons, which rise upon the urface of first fusion. Dissolves cyanite, forms with it an almost transpa- rent and colour- less glass, but somewhat mil ky. (^De Suns- sure.) Exhibits no gn of becom- ing soft, hard ens and con tract*. (Mac qucr, La'voisii:r.) Blow-pipe and oxygen gas. the the and Melts into a white, semi- transparent ena- mel, and be- comes so hard as to cut glass. {^Laiioisier, Guy- ton, Ehrmann.) Geyer could not produce fu- sion, except ot' the thin edges. Melts in a few seconds; spreads and adheres to the coal; after which it burns and detonates till the whole is dissipated. The small por- tion of the resi- due that may be collected, efflo- resces in the air, and has the taste of slaked lime. This kind of inflammation \i a common cha- racter with me- tallic subc-tancef. ^08 Ci^IEMIStRV s The grains of platina became united ; the mass turned black, like iron scales. By pounding, a black and highly attracta ble powder may be detached. The remainder, again submitted to the fire, loses the property Of being attracta- ble. Platina ex- posed to the same fire, in cru cibles of porce lain, does not infflt ®r lose its brilliancy, and becomes more attractable. {Diircct) r ^^\ grains of I gold from a gui j nea, exposed I thrice to the fire 1 in porcelain cru H cibles, lost half a grain the first, and nothing the second time. Blow-pipe and atmospheric air. The grains of platina are not in the least al- tered. {Scrg mann.) f One penny- weight, 13 grs.of I copelled silver, lost 8 grs.in por- celain crucibles. A portion oi oxyd attacks the interior of the crucibies, and forms a spongy coat of a pale I yellowish white. I Silver, if vii- j pourised, breaks ^the crucibles. Burning-glass. Blow-pipe and oxygen gas. Platina ex- Crude platina posed to the fo- undergoes a cus of Tschirn-complete fusion, hausen's burn-land the metal di- ng-glass, at'vides into round length aggluti-jgiobules, if the nates ; but ir. thc:quantity does numerous expe- riments made in 1772 and 1773 not exceed 5 or 6 grains. Platina, purg- by the academi- ed of its magne- cians of Paris, it could not be melted. Parker's burn ing-glass melted less than two minutes, {KirxL'an.) tic sand, exhibits the same pheno- mena as .crude platina. (^La-voi- Melts on the Homberg and Gold ea.siiy coal, and re- Macquer melted melts ; and La- mains there and volatilised itivoisier gilded a without altera- vvith Tschirn- piece of silver, tion. {£.'rgma!!i;.ybausen's burn- by holding it M.de Saussure ing-glass. The over the gold in says, that it dis- latter even per- fusion, appears, and isceived a stratum entirelydissipat- of violet-colour- ed in smoke. ed oxyd. Cupelled ver unites, globules, turns into pour. sil- intc and va- A portion ofi It melts m 10 the metal is va-l^^conds, and pourised v.-ith- k"'"s to vapour out oxydizmg; an infinite num- ber of small glo- bules are thrown upon the stand. without taking fire. ^ When the heat is kept up with- out vaporising, the metal be- comes oxydized- but it is easily reduced, and af- terwards evapo- rates. (£;6r-' mann.') APPLIED TO THE ARTS. 209 It melts, and becomes oxydiz- ed. It formed a mass of a beau- tiful red in a por- celain crucible. It is oxydized and becomes green. Sometimes is converted in- to a gold yellow glass, extremely beautiful and transparent. It melts on cy- Exposed to the It was melted anite, and covers focus of the in 13 seconds ; it with a bril- liant black var- nish, colours the exterior flame green, and is en- tirely evaporat- ed. The cyanite remains white and pure. The fibre of cyanite being charged with fi- lings of Malacca tin, and sudden- lyintroduced in- to the middle of the flame, the| filings are partly dissipated in sparks ; the ex- terior flame is tinged with a ligiit purple. A thin stratum of yellowish glass remains upon the cyanite; but if the exterior flame be made to approach the filings, the tin become'; oxydiz- ed. This oxyd does not melt ; it appears, on the contrary, to be evaporated, and entirely dis- sipated Under this oxyd, the cyanite seems tinged with yel- low. ) burning-glass onlbubbles, emits a a stone stand, it!green flame, and passes into the is entirely vola- state of oxyd. tilised. (^Lavoi' s:cr, Ehrmann.^ It melts into a white globule, shining like sil- ver, from which rises a white, a- bundant, clear, and luminous smoke, if taken from the fire, there remains a vitreous, opaque, hard, and brittle matter, covered with small nee- dles. The tin is at length entire- ly volatilised. It instant! V" melts, bubbles, and becomes red. A white, thick smoke, accom- panied with a white flame, as- cends from it. The metal be- comes oxydized. (^Lifnoisicr.) Ehrmann ob- served a blue flame ; he adds, that one grain of tin is volatilised in 30 or 40 se- conds. VOL. I. 210 CHEMISTRY S5 Porcelain fire. It forms a yel- low aiid trans parent glass. Blow-pipe and atmospheric air. It tinges the exterior flame blue; it turns to transparent glass of a greenish yel- iow, and evapo rates, leaving behind a yellow tint. Burning-glass. paste of the per celain '' Iron became It enters into oxydised, and fusion, bubbles formed a mix- and sparkles; ture with theithen penetrates between the fi- bres of the cya- nite, which colours a bright, then a dull black, and after wards a trans parent bottle green, which at last becomes clear. It melts and inflames, produ' cing much flaky oxyd. It rtielts, takes fire, and produ- ces a white, woolly oxyd. Minium is con verted into ; beautiful, bril liant litharge without reduc- tion. White lead melts instanta neously, emit- ting much smoke. One por- tion is converted into litharge the other vitrrfie the stone stand. Blow-pipe and oxygen gas. It burns in the fire, and produ^ ces brilliant tufts. (^Hombtrg.) It melts, be- comes covered withwiiite ox)d. U takes fire when this covering of oxyd is remov- ed. It immediately melts, and emit* a reddish smoke with flame. If exposed lowly to the fire, it becomes oxydized. This oxyd afterwards melts and evapo- rates ; and when the heat is in- creased the mat- ter burns with i. white flame. (Laioisier^ It melts, be- comes red, and burns, emitting small stars, which are scat- tered like a shower of stars. These particles, when united, are small, hollow, and brittle balls. It melts, be- comes red, and burns. The flame is red towards the middle, and blue at the point. It emits a great quantity of flaky oxyd. ■ FPLIED TO THE ARTS. 211 S 2 CIS « Porcelain fire. It runs, and is converted int glass of a pal( transparent vio- let, the colour of clear wine-lees. f* Darcet cal I cined and melt- 1 ed it into an o- ! paque and darl ^ blue mass. r It attacks and softens the paste of porcelain. Blov.'-pipe and atmospheric air. The tilinos laid upon the piece of cyanite, and slov^ly advanced to the flame, crack, sparkle, gives a violet tint to the exte- rior flame, and a yellowish smoke, hich adheres to the surround- ing objects, and is converted in- to a greenish yellow ' glass, which grows darker, and af- terwards evapo- rates gradually, leaving a pale, purplish tint, and some indi cations of corro- sion. Enters into fu sion; and if the fire is kept up, but not too strong, at length forms a dark violet mass. It inflames when suddenly exposed to the fire. (^Bcrgmann.) Burning-glas Ditto. Blow-pipe and oxygen gas. It burns with a whitish flame, which soon be- comes yellow. Themetalswells, flies out of the crucible, and makes yellow or brown spots on whatever it touches. One grain maybe vo- latised in 15 se- conds. (£.6r- manti.') P "^i Becomes red, melts, and burns, with a blueish flame,approach- ing to violet, ome sparks es- cape from the crucible. It burns with a light blue flame, and is dis- sipated, at the same time emit- Iting a smeU of 'garlic. 2\2 CHEMISTRY 6 2 Porcelain fire. ■ From 54 grains there was but a very small por- tion of regulus, which was cal- cined The glass is of a beautiful aad highly transpa' rent yellow. Blow-pipe and atmospheric air. It smokes, and inges the exte rior flame light blue; then leaves darkish grey spot, which is at length effaced but with diffi- culty. Burning-glass. It melts, smokes, and is entirely dissi- pated. The little hol- low in the stone, n which was the regulus, was co vered with a vi trifled coating of a light greenish yellow, with some black spots, and some appearances of purplish veins, Blow-pipe and oxygen gat. It melts in 10 seconds, and e« mits a white smoke. It be- comes red, and burns with a white flame. [Loi/oisier.) One grain is volatilised in 30 seconds. {El/r~ mann.) APPLIED TO THE ARTS. 91^ ARTICLE II. Ihhk of the Action of Heat on certain compound Substances. £ 2 ^1 Porcelain fire. Crystallized j^psum of Montmartre produces a beau- tiful transparent glass. This glass penetrates and dissolves the cm cibles. Striated, o: silky gypsum exhibits the same phenomena. Blow-pipe and atmospheric air. Crystallized gypsum of Burning-glass. Gypsum of Montmartre, Montmatre ex- calcined and foliates, becomeS|Wetted, and first white, and melts gently warmed into a snow whjtepaste. On the cya- nite it bubbles a ittle,becomes se- mi-transparent, penetrates, and corrodes. out of the focus, smoked a little, then being sub- mitted to the fo- cus, after shrink ingconsiderably, it opened in se- veral places, and at length melted into a matter which formed milk-white mas- ses, semi-trans- parent, like por- celain. {Muc^ qucr. Blow-pipe and oxygen gas. pure of Very gypsum Montmartre, previously cal- cined, bubbled and melted. (^Lavoisier.) Ehrmann melt- ed all the gyp- sums on which he operated. N. B. Gerard observed, that the gypsums become more solid in cru- cibles of chalk or coal, whereas they vitrify in those of argil. It appears, as Lavoisier has asserted, that, when the fire has been able to volatilise all the sulphuric acid, then the residue, being infusible, is liable to deceive the operator in various experiments tried upon that sulphate. 214 CHEMISTRY Porcelain fire. of r Fluates lime melt at degree of heat more or less vio- lent, according to their purity. The glass is more or less coloured; it assails the cru- cible, which it corrodes and d solves. Blov?-pipe and atmospheric air. *' This stone melted in a por celain fire ; it as sails the cruci- bles, which covers with coating of glass, like the fusible spars. Octagonal, transparent, greenish fluor spar forms cau- liflowers, of a dull, opaque, snow-white. On the cya- nite a fragment melted into a very transpa- rent, colourless glass. {Saussuie.) Cubic fluor spar of the Vos- ges,and the same par coloured did not melt in the focus of Tschirnhausen's burning-glass on stone stand but they formed round fluid globule, which, as it cooled, be me of an ena^ mel white. {La o'uier.) Ponderous, The ponderous transparent, co- spar of Sainte lourless spar, de- Marie aux crepitates, tinges Mines, exposed the exterior to the focus of flame green, andi Tschirnhausen't., when melted is burning - glass, land lamellated Blow-pipe and oxygen gas. Fluor spar of the Vosges melt^ ed into a glass, clear and trans- parent as water. The globule, as it grew cold, be- came opaque ; it had no longer the glassy polish of spar ; but re- sembled a melt- ed salt, and ea- ly ciiimbled to powder. (Z,a- vo'isicr.') The ponder- ous ■ spar of ainte Marie Mines, of the most beautiful opaque white of a dull, and al- most opaque white. On the cya- nite, after hav' ing tinged the flame green, it melts into a transparent, yel- lowish glass, which corrodes 5'owly,and with out efierves' cence. [Sansuirc.) on a stone standJstructure, burns calcined without with detonation. fusion ; but be ing put into : concavity in the coal, it under- went a kind o; combustion, c- mitted sulphu- reous vapours and left a lime which retained the taste of sul- phur of alkali {Lan/o'isier.) ! It leaves on the coal a white, a- crid, and bitter coating, with a taste of sul- pluir of alkali. The analysis of it proved it to be sulphur of barj'tes. {Lw •voisier.) APPLIED TO THE ARTS. 215 We arc indebted to Messrs. Darcet, Ehr- man, Giijton, Morveau^ Kirwan, and other cbemistS;, for very interesting experiments on the manner in which the mixtures of certain primary matters constantly employed in the same proportions;, are affected by va- rious determined degrees of heat. I think it useful to give a statement of their results in this place ; they will be of service to all those who are engaged in pyrotechnical operations. 1. DarceV^ ETperiments ivith the Porcelain Furnace. Mixtures. Results. a. E(jUiil parts of quartz and An unconnected matter, slaked lime. b. Equal men'^ures of \e.r\ hard spar and slaked lime. c. Equal measures of fine gypsum and slaked lime ot' marble. il. Equal measures of fine gypsum andvvhite argil- laceous earth. : Tvlelied, and formed a vi- treous, opaque mass. Opaque glass. White, semi-transparent ena- mel. 216 CHEMISTRY IMixtures. e. Three measures of tine gypsum, and one ot washed kaolin. f. Equal measures of g}^psum and gun-flint. g. Two measures of plaster, and one of fusible spar. h. Equal measures of fine gypsum and Never's sand. i. Eight measures of Never's sand, and a fusible spar. I. Eight meaures of fusible spar, and two of Brian- gon chalk. vi. One measure of gun-flint, two measures of fusible spar, three measures of fine gypsum. It. Equal measures of fine gypsum, pure argil, and hard spar. 0. Equal measures of fine gypsum, soft spar, and Champagne chalk. p. Fine gypsum, soft spar, one measure of each ; Champagne chalk two measures. Results. Hard, white, opaque, glass, forming a beautiful ena- nitrl, A very hard, solid mass, striking fire with a steel, A beautiful semi-transp^irgnt glass. A beautifiil semi-transparent glass. A hard solid mass. Semi- transparent enamel. Glass imperfectly melted. Opaque glass, of a milk- white. Opaque glass, very solid j good enamel. A spongy, opaque, white matter. Opaque glass, of a yellowish green. APPLIED TO THE ARTS. 217 Mixtures, q. Equal measures of plaster, pure argil, and Cham- pagne chalk. r. Equal measures of fine gypsum, pure argil, and Hints. Results. Glass, half transparent,, of a beautiful white. Glass of a light green, ap- proaching lo yelloWj and transparent. M. Guyton Morveau tried the action of two degrees of heat^ the lowest of which was from twenty-three to twenty-eight degrees, and the highest one hundred and thirty-four degrees, of Wedgwood's scale, on various earthy mix- tures. For the first blast the crucibles were placed under the muffle of the cupelling furnace. For the second they were exposed under a leversed crucible in Macquer's furnace, 218 CHEMISTRY A white matter, ., . , , slitrhtlvaG-g-iutinated Alumine 1 gram. )\ ° i- \ . ,r ■ , ° < separating: between Alay-nesia 1 CHEIVJISTUY designed (o ascertain the degree of heat, do not measure the quantity that may be contained in a body, which, however, it is of great import- ance in many cases to know. To remedy this great defect, or to fill up this chasm in the sci- ence of pyrometry, Messrs. Laplace and La- voisier contrived an apparatus capable of de- termining the total quantity of caloric which may be disengaged from a body, till its tem- perature be reduced to that of ice. They give to it the appellation of calorimeter) and it is founded on the principle that ice absorbs heat» without communicating any till it is melted. In order to obtain correct results, it w as nCr cessary : \. To discover the means of causing all the hpat that is disengaged from a body to be absorbed by ice ; 2. To skreen the ice from the action of any other substance that may co- operate to melt it ; 3. To collect all the water produced by its fusion. The apparatus constructed for this purpose by the two celebrated academicians, consists of three circular bodies, fixed nearly one in the other, so as to produce three vacancies {Plate. X. jig. 1 & 2.) The interior vacancy eet APPLIED TO THE ARTS. ^33 (Jig. 2.) is formed of iron wire-workj supported by props of the same metal. In this space are put the bodies submitted to experiment ; it is covered with a top likewise formed of wirer work. The middle vacancy bhbb (jig. 2. J is designed to contain the ice which is placed all round the inside. The ice is supported and kept at the bottom by very close wire-work. This space is separated from the inner one only by the grating. As the ice melts the water runs through the wire-work into the cavity ec (Jig. 2.) and is received in the vase e fji^. 1.) when the cock d (fig. 2.) is opened. The outer space aaaa, contains the ice which en- velopes the middle one^ and prevents the access of the external heat. The water formed in this pavity escapes by the pipe lih (fig. 2.) and runs into a distinct vessel. This space is se- parated from the middle one by a partition of tin or copper, so that there is no couimunica- lion between them. In order to use this ingenious apparatus, the Toniddle space and the covering of the interior sphere are filled with pounded ice. The ex- terior space is filled with the same substance. 2Si CHEMISTRY which is also spread over the general cover of the whole machine. Drain the interior ice ; do the same with that in the outer S] ace, and in the general covering of the whole machine When the interior ice ceases to furnish any water, take off the cover to introduce thehodv, and put it on again immediately. Collect with care all the water that runs off, till the tem- perature of the hodv be red^iced to that of the ice. It is evident that the weight of the water obtained affords the exact measure of the heat disengaged from the body, which alone occa- sions the fusion. It is necessary that the heat of the atmos- pbrre shopld not be below zero, because then the interior ice would receive a degree of cold under that point. The speciiic heat being nolhing more than the proportion between the quantity of heat necessary to raise to the same number of degrees^, the temperature of bodies equal in mass, it fol- lows, that to obtain the specific caloric of a solid body, you must elevate its temperature to a,ny number of degrees, place it quickly in ths APPLIED TO THE ARTS. 235 interior sphere^ and leave it there till its tem- perature lias . ' 'It.i to zero. Collect the water, and its quantity^ divided by the product of the liiass of the body, and the number of d^^^grees which its primitive temperature was t bove zeroj will give the proportion of tbe sp^jcific heat. To ascertain the heat of fluids cnc -e the vessels in the calorimeter, in order to i luce the heat to the temperature of ice, and then quickly pour off the liquids. To determine the heat of respiration, and of gaseous matters, form a communicatio.i by means of tubes between the interior sphere, ^nd the external body which contains the air subjected to experiment, and you may establish a circulation between the exterior and iiiioiior, which is kept up till the air under experiment ceases to melt the ice. The c^uantity of heat given oiii by the air on its passage may be esti- mated bv holdina; two thermometers to the two prifices for ingress and egress. ENP OF VOL. I. I EXPLANATION OF THE PLATES IN THE FIRST VOLUME. PLATE L Figure 1, represents the forge of a laboratory ■vvitli its bellows. aa. The bellows. hb. The forge. c. The support of the forge. d. The fire-place. e. The dome. f. The chimney. g. The door of the dome. Figure 2, represents a laboratory forge with a triple current of air. aa. Bellows with a double pipe. 238 EXPLANATION OF THE PLATES. hb. Reservoir of air. ccc. Tubes which convey the air to the forge, dddd. Square forge. e. Interior of the forge. ff. Contraction of the forge to receive the cover. gggg' Thickness and sides of the forge. 22. The cover of the forge. 222. The grate. Figure S, represents the section of the forge with a triple current of air. ccc. Apertures by which the air of the three tubes passes into the forge. ee. Bottom, or floor of the forge. dd. Contraction of the forge to receive the grate. gg. Upper contraction to receive the cover. ffff. Thickness of the sides of the forge. Figure 4^ represents a crucible. 44. The iid of a crucible. Ri.kbjhed.Jun EXPLANATION OF THE PLATES: dJ)b. Caskin which it is placed. ccc. Stand on which the cask^ containing the worm, is placed. dd. End, or mouth of the worm, from which runs the liquid under dis- tillation. e. Upper aperture of the worm, which receives the end of the neck of the alembic. Figure 3, represents a furnace with an alembic and a worm. aa. Furnace in w^hich the alembic is fixed. bh. Body, and upper part of the boiler. cc. Aperture by which the boiler is filled. dd. Head which covers the boiler. ce. Neck of the boiler. //. Junction of the neck with the upper end of the worm. gg. The worm, represented bj dotted lines rn the cask. Fi^ J Fi^ J jPlaif lo.Vo/ T. EXPLA^fATION OF THE rLATE-'; 277 h. Lower end of the worm. iii. A pipe to receive the sapcrabiindant water of the cask in which the worm is placed, kk. A pipe intended to convey cold wa- ter into the cask. IIL The cask in which the worm is flxrd, mm. The stand which supports the cask. Ji'igure 4, represents the interior of (he fiir- nace. For the explanation, see Plate V; 111^. 1; PhXTE Xi Figure 1 , represents a calorimeter. aa. Envelopes of the caiorimctof. bb. Covers of the three spaces of the ca- lorimeter, c. Cock and pipe for discha-gin^ thd melted ice from the tljird sp:*.c?, tOL. I, « 258 EXPLANATION OF THE PLATES. d. Cock and pipe for discharging the melted ice from the middle space. €. Vessel to receive the water which runs from the middle space. /. The stand. gg. The general coyer of the whole ca- lorimeter. Figure 2, represents a vertical section of a ca- lorimeter. aa. Exterior space filled with pounded ice. b'j. jMiddie space filled with pounded ice. cc. The central space^, separated from the middle one by an iron grating. d. End of the channel by which the melted ice of the middle space is discharged. ee. The bottom of the grate, which hold§ the ice of the middle space, /, Caver of the central space. gg. The top of the calorimeter covering the three spaces^ and charged v/ith ice. EXPLANATION OF THE PLATES- 259 hh. Channel for discliargiqg the melted ice of the third space. a. Top of the cover of the third space, charged with ice. Figure Sj represents the internal grating. T. Gillet, Printer, Wild-court, Lincoln's-Inn-Fleklj. CDtii. %5-6 5PEC)*+L 5-^1^ rp v/' 1 iH^l ^ilp : 1 1 ■ 1 UBRARY f'-^^ 1 J' ^ 'f r y ^ i H / * 41 r i\i /f f'N r /